Bash Commands

Bash Commands That Save Me Time and Frustration

Here's a list of bash commands that stand between me and insanity.


Bash Commands That Save Me Time and Frustration

Here's a list of bash commands that stand between me and insanity.

https://bryanguner.medium.com/a-list-of-all-of-my-articles-to-link-to-future-posts-1f6f88ebdf5b

This article will be accompanied by the following > github repository > which will contain all the commands listed as well as folders that demonstrate before and after usage!

bgoonz/bash-commands-walkthrough
to accompany the medium article I am writing. Contribute to bgoonz/bash-commands-walkthrough development by creating an…github.com

The readme for this git repo will provide a much more condensed list… whereas this article will break up the commands with explanations… images & links!

I will include the code examples as both github gists (for proper syntax highlighting) and as code snippets adjacent to said gists so that they can easily be copied and pasted… or … if you're like me for instance; and like to use an extension to grab the markdown content of a page… the code will be included rather than just a link to the gist!

Here's a Cheatsheet:

Getting Started (Advanced Users Skip Section):


✔ Check the Current Directory ➡ pwd:

On the command line, it's important to know the directory we are currently working on. For that, we can use pwd command.

It shows that I'm working on my Desktop directory.

✔ Display List of Files ➡ ls:

To see the list of files and directories in the current directory use ls command in your CLI.

Shows all of my files and directories of my Desktop directory.
  • To show the contents of a directory pass the directory name to the ls command i.e. ls directory_name.
  • Some useful ls command options:-

OptionDescriptionls -alist all files including hidden file starting with '.'ls -llist with the long formatls -lalist long format including hidden files

✔ Create a Directory ➡ mkdir:

We can create a new folder using the mkdir command. To use it type mkdir folder_name.

Use `ls` command to see the directory is created or not.

I created a cli-practice directory in my working directory i.e. Desktop directory.

✔ Move Between Directories ➡ cd:

It's used to change directory or to move other directories. To use it type cd directory_name.

Can use `pwd` command to confirm your directory name.

Changed my directory to the cli-practice directory. And the rest of the tutorial I'm gonna work within this directory.

✔ Parent Directory ➡ ..:

We have seen cd command to change directory but if we want to move back or want to move to the parent directory we can use a special symbol .. after cd command, like cd ..

✔ Create Files ➡ touch:

We can create an empty file by typing touch file_name. It's going to create a new file in the current directory (the directory you are currently in) with your provided name.

I created a hello.txt file in my current working directory. Again you can use `ls` command to see the file is created or not.

Now open your hello.txt file in your text editor and write Hello Everyone! into your hello.txt file and save it.

✔ Display the Content of a File ➡ cat:

We can display the content of a file using the cat command. To use it type cat file_name.

Shows the content of my hello.txt file.

✔ Move Files & Directories ➡ mv:

To move a file and directory, we use mv command.

By typing mv file_to_move destination_directory, you can move a file to the specified directory.

By entering mv directory_to_move destination_directory, you can move all the files and directories under that directory.

Before using this command, we are going to create two more directories and another txt file in our cli-practice directory.

mkdir html css touch bye.txt

Yes, we can use multiple directories & files names one after another to create multiple directories & files in one command.
Moved my bye.txt file into my css directory and then moved my css directory into my html directory.

✔ Rename Files & Directories ➡ mv:

mv command can also be used to rename a file and a directory.

You can rename a file by typing mv old_file_name new_file_name & also rename a directory by typing mv old_directory_name new_directory_name.

Renamed my hello.txt file to the hi.txt file and html directory to the folder directory.

✔ Copy Files & Directories ➡ cp:

To do this, we use the cp command.

  • You can copy a file by entering cp file_to_copy new_file_name.
Copied my hi.txt file content into hello.txt file. For confirmation open your hello.txt file in your text editor.
  • You can also copy a directory by adding the -r option, like cp -r directory_to_copy new_directory_name.

The -r option for "recursive" means that it will copy all of the files including the files inside of subfolders.

Here I copied all of the files from the folder to folder-copy.

✔ Remove Files & Directories ➡ rm:

To do this, we use the rm command.

  • To remove a file, you can use the command like rm file_to_remove.
Here I removed my hi.txt file.
  • To remove a directory, use the command like rm -r directory_to_remove.
I removed my folder-copy directory from my cli-practice directory i.e. current working directory.

✔ Clear Screen ➡ clear:

Clear command is used to clear the terminal screen.

✔ Home Directory ➡ ~:

The Home directory is represented by ~. The Home directory refers to the base directory for the user. If we want to move to the Home directory we can use cd ~ command. Or we can only use cd command.


MY COMMANDS:

1.) Recursively unzip zip files and then delete the archives when finished:

here is a folder containing the before and after… I had to change folder names slightly due to a limit on the length of file-paths in a github repo.

find . -name "*.zip" | while read filename; do unzip -o -d "`dirname "$filename"`" "$filename"; done;

find . -name "*.zip" -type f -print -delete

2.) Install node modules recursively:

npm i -g recursive-install

npm-recursive-install

3.) Clean up unnecessary files/folders in git repo:

find . -empty -type f -print -delete #Remove empty files

# -------------------------------------------------------
find . -empty -type d -print -delete #Remove empty folders

# -------------------------------------------------------

# This will remove .git folders...    .gitmodule files as well as .gitattributes and .gitignore files.

find . \( -name ".git" -o -name ".gitignore" -o -name ".gitmodules" -o -name ".gitattributes" \) -exec rm -rf -- {} +

# -------------------------------------------------------

# This will remove the filenames you see listed below that just take up space if a repo has been downloaded for use exclusively in your personal file system (in which case the following files just take up space)# Disclaimer... you should not use this command in a repo that you intend to use with your work as it removes files that attribute the work to their original creators!

find . \( -name "*SECURITY.txt" -o -name "*RELEASE.txt" -o -name "*CHANGELOG.txt" -o -name "*LICENSE.txt" -o -name "*CONTRIBUTING.txt" -name "*HISTORY.md" -o -name "*LICENSE" -o -name "*SECURITY.md" -o -name "*RELEASE.md" -o -name "*CHANGELOG.md" -o -name "*LICENSE.md" -o -name "*CODE_OF_CONDUCT.md" -o -name "\*CONTRIBUTING.md" \) -exec rm -rf -- {} +

In Action:

The following output from my bash shell corresponds to the directory:

bgoonz/bash-commands-walkthrough
Deployment github-pages Navigation Big O notation is the language we use for talking about how long an algorithm takes…github.com

which was created by running the aforementioned commands in in a perfect copy of this directory:

bgoonz/DS-ALGO-OFFICIAL
Deployment github-pages Navigation Big O notation is the language we use for talking about how long an algorithm takes…github.com

…..below is the terminal output for the following commands:

pwd
/mnt/c/Users/bryan/Downloads/bash-commands/steps/3-clean-up-fluf/DS-ALGO-OFFICIAL-master

After printing the working directory for good measure:

find . -empty -type f -print -delete

The above command deletes empty files recursively starting from the directory in which it was run:

./CONTENT/DS-n-Algos/File-System/file-utilities/node_modules/line-reader/test/data/empty_file.txt
./CONTENT/DS-n-Algos/_Extra-Practice/free-code-camp/nodejs/http-collect.js
./CONTENT/Resources/Comments/node_modules/mime/.npmignore
./markdown/tree2.md
./node_modules/loadashes6/lodash/README.md
./node_modules/loadashes6/lodash/release.md
./node_modules/web-dev-utils/Markdown-Templates/Markdown-Templates-master/filled-out-readme.md
|01:33:16|bryan@LAPTOP-9LGJ3JGS:[DS-ALGO-OFFICIAL-master] DS-ALGO-OFFICIAL-master_exitstatus:0[╗___________o>

The command seen below deletes empty folders recursively starting from the directory in which it was run:

find . -empty -type d -print -delete

The resulting directories….

|01:33:16|bryan@LAPTOP-9LGJ3JGS:[DS-ALGO-OFFICIAL-master] DS-ALGO-OFFICIAL-master_exitstatus:0[╗___________o>

find . -empty -type d -print -delete
./.git/branches
./.git/objects/info
./.git/refs/tags
|01:33:31|bryan@LAPTOP-9LGJ3JGS:[DS-ALGO-OFFICIAL-master] DS-ALGO-OFFICIAL-master_exitstatus:0[╗___________o>

The command seen below deletes .git folders as well as .gitignore, .gitattributes, .gitmodule files

find . \( -name ".git" -o -name ".gitignore" -o -name ".gitmodules" -o -name ".gitattributes" \) -exec rm -rf -- {} +

The command seen below deletes most SECURITY, RELEASE, CHANGELOG, LICENSE, CONTRIBUTING, & HISTORY files that take up pointless space in repo's you wish to keep exclusively for your own reference.

!!!Use with caution as this command removes the attribution of the work from it's original authors!!!!!

!!!Use with caution as this command removes the attribution of the work from it's original authors!!!!!
!!!Use with caution as this command removes the attribution of the work from it's original authors!!!!!
find . \( -name "*SECURITY.txt" -o -name "*RELEASE.txt" -o -name "*CHANGELOG.txt" -o -name "*LICENSE.txt" -o -name "*CONTRIBUTING.txt" -name "*HISTORY.md" -o -name "*LICENSE" -o -name "*SECURITY.md" -o -name "*RELEASE.md" -o -name "*CHANGELOG.md" -o -name "*LICENSE.md" -o -name "*CODE_OF_CONDUCT.md" -o -name "*CONTRIBUTING.md" \) -exec rm -rf -- {} +

4.) Generate index.html file that links to all other files in working directory:

#!/bin/sh
# find ./ | grep -i "\.*$" >files
find ./ | sed -E -e 's/([^ ]+[ ]+){8}//' | grep -i "\.*$">files
listing="files"
out=""
html="index.html"
out="basename $out.html"
html="index.html"
cmd() {
  echo '  <!DOCTYPE html>'
  echo '<html>'
  echo '<head>'
  echo '  <meta http-equiv="Content-Type" content="text/html">'
  echo '  <meta name="Author" content="Bryan Guner">'
  echo '<link rel="stylesheet" href="./assets/prism.css">'
  echo ' <link rel="stylesheet" href="./assets/style.css">'
  echo ' <script async defer src="./assets/prism.js">

' echo " directory " echo "" echo '' echo '' echo '' echo "" # continue with the HTML stuff echo "" echo "" echo "

    " awk '{print "
  • <a href=""$1"">",$1," 

"}' $listing # awk '{print "
  • "}; # {print " ",$1,"
  •  "}' \ $listing echo "" echo "" echo "" echo "" } cmd $listing --sort=extension >>$html

    In Action:

    I will use this copy of my Data Structures Practice Site to demonstrate the result:

    side-projects-42/DS-Bash-Examples-Deploy
    Deployment github-pages Navigation Big O notation is the language we use for talking about how long an algorithm takes…github.com
    #### The result is a index.html file that contains a list of links to each file in the directory:

    here is a link to and photo of the resulting html file:

    index.html
    CONTENT/DS-n-Algos/quirky-meninsky-4181b5.netlify.app

    5.) Download all links to a files of a specified extension on a user provided (url) webpage:

    wget -r -A.pdf https://overapi.com/gitwget --wait=2 --level=inf --limit-rate=20K --recursive --page-requisites --user-agent=Mozilla --no-parent --convert-links --adjust-extension --no-clobber -e robots=off

    The result is stored in this directory:


    6.)Recursively remove lines of text containing the string badFolder from files in the working directory.

    find . -type f -exec sed -i '/badFolder/d' ./* {} \;
    
    # OR
    
    find . -name 'result.md'  -type f -exec sed -i '/badFolder/d' ./* {} \;

    As an example I will run this command on a file containing the text:

    Hacks Blog
    
    Read more at hacks.mozilla.org
    
    badFolder
    
    badFolder Implementing Private Fields for JavaScript
    
    When implementing a language feature for JavaScript, an implementer must make decisions about how the language in the specification maps to the implementation. Private fields is an example of where the specification language and implementation reality diverge, at least in SpiderMonkey- the JavaScript engine which powers Firefox. To understand more, I'll explain what private fields are, a couple of models for thinking about them, and explain why our implementation diverges from the specification language.The post Implementing Private Fields for JavaScript appeared first on Mozilla Hacks - the Web developer blog.
    
    Posted Tuesday, June 8, 2021 by Matthew Gaudet
    
    Looking fine with Firefox 89
    
    Firefox 89 has smartened up and brings with it a slimmed-down, slightly more minimalist interface.badFolder Along with this new look, we get some great styling features including a force-colours feature for media queries and better control over how fonts are displayed. The long-awaited top-level await keyword for JavaScript modules is now enabled, as well as the PerformanceEventTiming interface, which is another addition to the performance suite of APIs: 89 really has been working out!The post Looking fine with Firefox 89 appeared first on Mozilla Hacks - the Web developer blog.
    
    badFolder
    
    Posted Tuesday, June 1, 2021 by Chris Mills
    
    badFolder
    
    Improving Firefox stability on Linux
    
    Roughly a year ago at Mozilla we started an effort to improve Firefox stability on Linux. This effort quickly became an example of good synergies between FOSS projects.The post Improving Firefox stability on Linux appeared first on Mozilla Hacks - the Web developer blog.
    
    Posted Wednesday, May 19, 2021 by Gabriele Svelto badFolder
    
    Introducing Firefox's new Site Isolation Security Architecture
    
    Like any web browser, Firefox loads code from untrusted and potentially hostile websites and runs it on your computer. To protect you against new types of attacks from malicious sites and to meet the security principles of Mozilla, we set out to redesign Firefox on desktop.The post Introducing Firefox's new Site Isolation Security Architecture appeared first on Mozilla Hacks - the Web developer blog.
    
    Posted Tuesday, May 18, 2021 by Anny Gakhokidze
    
    Pyodide Spin Out and 0.17 Release
    
    We are happy to announce that Pyodide has become an independent and community-driven project. We are also pleased to announce the 0.17 release for Pyodide with many new features and improvements. Pyodide consists of the CPython 3.8 interpreter compiled to WebAssembly which allows Python to run in the browser.The post Pyodide Spin Out and 0.17 Release appeared first on Mozilla Hacks - the Web developer blog. badFolder
    
    Posted Thursday, April 22, 2021 by Teon Brooks

    I modified the command slightly to apply only to files called 'result.md':

    The result is :

    Hacks Blog
    
    Read more at hacks.mozilla.org
    
    When implementing a language feature for JavaScript, an implementer must make decisions about how the language in the specification maps to the implementation. Private fields is an example of where the specification language and implementation reality diverge, at least in SpiderMonkey- the JavaScript engine which powers Firefox. To understand more, I'll explain what private fields are, a couple of models for thinking about them, and explain why our implementation diverges from the specification language.The post Implementing Private Fields for JavaScript appeared first on Mozilla Hacks - the Web developer blog.
    
    Posted Tuesday, June 8, 2021 by Matthew Gaudet
    
    Looking fine with Firefox 89
    
    Posted Tuesday, June 1, 2021 by Chris Mills
    
    Improving Firefox stability on Linux
    
    Roughly a year ago at Mozilla we started an effort to improve Firefox stability on Linux. This effort quickly became an example of good synergies between FOSS projects.The post Improving Firefox stability on Linux appeared first on Mozilla Hacks - the Web developer blog.
    
    Introducing Firefox's new Site Isolation Security Architecture
    
    Like any web browser, Firefox loads code from untrusted and potentially hostile websites and runs it on your computer. To protect you against new types of attacks from malicious sites and to meet the security principles of Mozilla, we set out to redesign Firefox on desktop.The post Introducing Firefox's new Site Isolation Security Architecture appeared first on Mozilla Hacks - the Web developer blog.
    
    Posted Tuesday, May 18, 2021 by Anny Gakhokidze
    
    Pyodide Spin Out and 0.17 Release
    
    Posted Thursday, April 22, 2021 by Teon Brooks

    the test.txt and result.md files can be found here:

    bgoonz/bash-commands-walkthrough
    to accompany the medium article I am writing. Contribute to bgoonz/bash-commands-walkthrough development by creating an…github.com

    7.) Execute command recursively:

    Here I have modified the command I wish to run recursively to account for the fact that the 'find' command already works recursively, by appending the -maxdepth 1 flag…

    I am essentially removing the recursive action of the find command…

    That way, if the command affects the more deeply nested folders we know the outer RecurseDirs function we are using to run the find/pandoc line once in every subfolder of the working directory… is working properly!

    **Run in the folder shown to the left… we would expect every .md file to be accompanied by a newly generated html file by the same name.**

    The results of said operation can be found in the following directory

    In Action:

    🢃 Below 🢃

    The final result is:

    If you want to run any bash script recursively all you have to do is substitue out line #9 with the command you want to run once in every sub-folder.

    function RecurseDirs ()
    {
        oldIFS=$IFS
        IFS=$'\n'
        for f in "$@"
        do
    
    #Replace the line below with your own command!
    
    #find ./ -iname "*.md" -maxdepth 1 -type f -exec sh -c 'pandoc --standalone "${0}" -o "${0%.md}.html"' {} \;
    
    #####################################################
    # YOUR CODE BELOW!
    
    #####################################################
    
    if [[ -d "${f}" ]]; then
                cd "${f}"
                RecurseDirs $(ls -1 ".")
                cd ..
            fi
        done
        IFS=$oldIFS
    }
    RecurseDirs "./"

    TBC….

    Here are some of the other commands I will cover in greater detail… at a later time:

    9. Copy any text between <script> tags in a file called example.html to be inserted into a new file: out.js

    sed -n -e '/<script>/,/<\/script>/p' example.html >out.js

    10. Recursively Delete node_modules folders

    find . -name 'node_modules' -type d -print -prune -exec rm -rf '{}' +

    11. Sanatize file and folder names to remove illegal characters and reserved words.

    sanitize() {
      shopt -s extglob;
    
      filename=$(basename "$1")
      directory=$(dirname "$1")
    
      filename_clean=$(echo "$filename" | sed -e 's/[\\/:\*\?"<>\|\x01-\x1F\x7F]//g' -e 's/^\(nul\|prn\|con\|lpt[0-9]\|com[0-9]\|aux\)\(\.\|$\)//i' -e 's/^\.*$//' -e 's/^$/NONAME/')
    
      if (test "$filename" != "$filename_clean")
      then
        mv -v "$1" "$directory/$filename_clean"
      fi
    }
    
    export -f sanitize
    
    sanitize_dir() {
      find "$1" -depth -exec bash -c 'sanitize "$0"' {} \;
    
    }
    
    sanitize_dir '/path/to/somewhere'

    12. Start postgresql in terminal

    sudo -u postgres psql

    13. Add closing body and script tags to each html file in working directory.

    for f in * ; do
      mv "$f" "$f.html"
    doneecho "<form>
     <input type="button" value="Go back!" onclick="history.back()">
    </form>
      </body>
    " | tee -a *.html

    14. Batch Download Videos

    #!/bin/bash
    
    link="#insert url here#"
    #links were a set of strings with just the index of the video as the variable
    
    num=3
    #first video was numbered 3 - weird.
    
    ext=".mp4"
    
    while [ $num -le 66 ]
    do
          wget $link$num$ext -P ~/Downloads/
          num=$(($num+1))
    done

    15. Change File Extension from '.txt' to .doc for all files in working directory.

    sudo apt install rename
    
    rename 's/\.txt$/.doc/' *.txt

    16. Recursivley change any file with extension .js.download to .js

    find . -name "*.\.js\.download" -exec rename 's/\.js\.download$/.js/' '{}' +

    17. Copy folder structure including only files of a specific extension into an ouput Folder

    find . -name '*.md' | cpio -pdm './../outputFolder'

    Discover More:

    Web-Dev-Hub
    Memoization, Tabulation, and Sorting Algorithms by Example Why is looking at runtime not a reliable method of…bgoonz-blog.netlify.app

    Part 2 of this series:

    Medium
    Continued!!!medium.com

    By Bryan Guner on June 29, 2021.

    Canonical link

    August 31, 2021.

    Resources:

    1. Remove spaces from file and folder names and then remove numbers from files and folder names....

    Description: need to : sudo apt install rename

    Notes: Issue when renaming file without numbers collides with existing file name...

    code:
    find . -name "* *" -type d | rename 's/ /_/g'find . -name "* *" -type f | rename 's/ /_/g'
    ```shell
    find $dir -type f | sed 's|\(.*/\)[^A-Z]*\([A-Z].*\)|mv \"&\" \"\1\2\"|' | shfind $dir -type d | sed 's|\(.*/\)[^A-Z]*\([A-Z].*\)|mv \"&\" \"\1\2\"|' | shfor i in *.html; do mv "$i" "${i%-*}.html"; donefor i in *.*; do mv "$i" "${i%-*}.${i##*.}"; done
    
    ---
    ### Description: combine the contents of every file in the contaning directory.>Notes: this includes the contents of the file it's self...
    
    ###### code:```js
    //
    //APPEND-DIR.js
    const fs = require('fs');let cat = require('child_process')
      .execSync('cat *')
      .toString('UTF-8');
    fs.writeFile('output.md', cat, err => {if (err) throw err;});

    2. Download Website Using Wget:

    Description:

    Notes: ==> sudo apt install wget

    code:
    wget --limit-rate=200k --no-clobber --convert-links --random-wait -r -p -E -e robots=off -U mozilla https://bootcamp42.gitbook.io/python/

    3. Clean Out Messy Git Repo:

    Description: recursively removes git related folders as well as internal use files / attributions in addition to empty folders

    Notes: To clear up clutter in repositories that only get used on your local machine.

    code:
    find . -empty -type d -print -deletefind . \( -name ".git" -o -name ".gitignore" -o -name ".gitmodules" -o -name ".gitattributes" \) -exec rm -rf -- {} +
    
    find . \( -name "*SECURITY.txt" -o -name "*RELEASE.txt" -o  -name "*CHANGELOG.txt" -o -name "*LICENSE.txt" -o -name "*CONTRIBUTING.txt" -name "*HISTORY.md" -o -name "*LICENSE" -o -name "*SECURITY.md" -o -name "*RELEASE.md" -o  -name "*CHANGELOG.md" -o -name "*LICENSE.md" -o -name "*CODE_OF_CONDUCT.md" -o -name "*CONTRIBUTING.md" \) -exec rm -rf -- {} +

    4. clone all of a user's git repositories

    Description: clone all of a user or organization's git repositories.

    Notes:

    code:

    Generalized:

    CNTX={users|orgs}; NAME={username|orgname}; PAGE=1curl "https://api.github.com/$CNTX/$NAME/repos?page=$PAGE&per_page=100" |grep -e 'git_url*' |cut -d \" -f 4 |xargs -L1 git clone

    Clone all Git User

    CNTX={users}; NAME={bgoonz}; PAGE=1curl "https://api.github.com/$CNTX/$NAME/repos?page=$PAGE&per_page=200"?branch=master |grep -e 'git_url*' |cut -d \" -f 4 |xargs -L1 git clone

    Clone all Git Organization:

    CNTX={organizations}; NAME={TheAlgorithms}; PAGE=1curl "https://api.github.com/$CNTX/$NAME/repos?page=$PAGE&per_page=200"?branch=master |grep -e 'git_url*' |cut -d \" -f 4 |xargs -L1 git clone

    5. Git Workflow

    Description:

    code:
    git pull
    git init
    git add .git commit -m"update"git push -u origin master
    git init
    git add .git commit -m"update"git push -u origin main
    git init
    git add .git commit -m"update"git push -u origin bryan-guner
    git init
    git add .git commit -m"update"git push -u origin gh-pages
    git init
    git add .git commit -m"update"git push -u origin preview

    6. Recursive Unzip In Place

    Description: recursively unzips folders and then deletes the zip file by the same name.

    Notes:

    code:
    find . -name "*.zip" | while read filename; do unzip -o -d "`dirname "$filename"`" "$filename"; done;find . -name "*.zip" -type f -print -delete

    7. git pull keeping local changes:

    Description:

    Notes:

    code:
    git stash
    git pull
    git stash pop

    8. Prettier Code Formatter:

    Description:

    Notes:

    code:
    sudo npm i prettier -g
    
    prettier --write .

    9. Pandoc

    Description:

    Notes:

    code:
    find ./ -iname "*.md" -type f -exec sh -c 'pandoc --standalone "${0}" -o "${0%.md}.html"' {} \;find ./ -iname "*.html" -type f -exec sh -c 'pandoc --wrap=none --from html --to markdown_strict "${0}" -o "${0%.html}.md"' {} \;find ./ -iname "*.docx" -type f -exec sh -c 'pandoc "${0}" -o "${0%.docx}.md"' {} \;

    10. Gitpod Installs

    Description:

    Notes:

    code:
    sudo apt install tree
    sudo apt install pandoc -ysudo apt install rename -ysudo apt install black -ysudo apt install wget -ynpm i lebab -gnpm i prettier -gnpm i npm-recursive-install -g
    black .
    
    prettier --write .
    npm-recursive-install

    11. Repo Utils Package:

    Description: my standard repo utis package

    Notes:

    code:
    npm i @bgoonz11/repoutils

    12. Unix Tree Package Usage:

    Description:

    Notes:

    code:
    tree -d -I  'node_modules'
    
    tree  -I  'node_modules'
    
    tree -f  -I  'node_modules' >TREE.md
    
    tree -f -L 2  >README.md
    
    tree -f  -I  'node_modules' >listing-path.md
    
    tree -f  -I  'node_modules' -d >TREE.md
    
    tree -f >README.md

    13. Find & Replace string in file & folder names recursively..

    Description:

    Notes:

    code:
    find . -type f -exec rename 's/string1/string2/g' {} +
    
    find . -type d -exec rename 's/-master//g' {} +
    
    find . -type f -exec rename 's/\.download//g' {} +
    
    find . -type d -exec rename 's/-main//g' {} +
    
    rename 's/\.js\.download$/.js/' *.js\.download
    
    rename 's/\.html\.markdown$/.md/' *.html\.markdown
    
    find . -type d -exec rename 's/es6//g' {} +

    14. Remove double extensions :

    Description:

    Notes:

    code:
    #!/bin/bashfor file in *.md.md
    domv "${file}" "${file%.md}"done#!/bin/bashfor file in *.html.html
    domv "${file}" "${file%.html}"done
    #!/bin/bashfor file in *.html.png
    domv "${file}" "${file%.png}"donefor file in *.jpg.jpg
    domv "${file}" "${file%.png}"done

    15. Truncate folder names down to 12 characters:

    Description:

    Notes:

    code:
    for d in ./*; do mv $d ${d:0:12}; done

    16.Appendir.js

    Description: combine the contents of every file in the contaning directory.

    Notes: this includes the contents of the file it's self...

    code:
    ////APPEND-DIR.jsconst fs = require('fs');let cat = require('child_process').execSync('cat *').toString('UTF-8');
    fs.writeFile('output.md', cat, (err) => {if (err) throw err;});

    17. Replace space in filename with underscore

    Description: followed by replace '#' with '_' in directory name

    Notes: Can be re-purposed to find and replace any set of strings in file or folder names.

    code:
    find . -name "* *" -type f | rename 's/_//g'find . -name "* *" -type d | rename 's/#/_/g'

    18. Filter & delete files by name and extension

    Description:

    Notes:

    code:
    find . -name '.bin' -type d -prune -exec rm -rf '{}' +
    
    find . -name '*.html' -type d -prune -exec rm -rf '{}' +
    
    find . -name 'nav-index' -type d -prune -exec rm -rf '{}' +
    
    find . -name 'node-gyp' -type d -prune -exec rm -rf '{}' +
    
    find . -name 'deleteme.txt' -type f -prune -exec rm -rf '{}' +
    
    find . -name 'right.html' -type f -prune -exec rm -rf '{}' +
    
    find . -name 'left.html' -type f -prune -exec rm -rf '{}' +

    19. Remove lines containing string:

    Description:

    Notes: Remove lines not containing '.js'

    sudo sed -i '/\.js/!d' ./*scrap2.md
    code:
    sudo sed -i '/githubusercontent/d' ./*sandbox.md
    
    sudo sed -i '/githubusercontent/d' ./*scrap2.md
    
    sudo sed -i '/github\.com/d' ./*out.md
    
    sudo sed -i '/author/d' ./*

    20. Remove duplicate lines from a text file

    Description:

    Notes: //...syntax of uniq...// $uniq [OPTION] [INPUT[OUTPUT]] The syntax of this is quite easy to understand. Here, INPUT refers to the input file in which repeated lines need to be filtered out and if INPUT isn't specified then uniq reads from the standard input. OUTPUT refers to the output file in which you can store the filtered output generated by uniq command and as in case of INPUT if OUTPUT isn't specified then uniq writes to the standard output.

    Now, let's understand the use of this with the help of an example. Suppose you have a text file named kt.txt which contains repeated lines that needs to be omitted. This can simply be done with uniq.

    code:
    sudo apt install uniquniq -u input.txt output.txt

    21. Remove lines containing string:

    Description:

    Notes:

    code:
    sudo sed -i '/githubusercontent/d' ./*sandbox.md
    
    sudo sed -i '/githubusercontent/d' ./*scrap2.md
    
    sudo sed -i '/github\.com/d' ./*out.md
    
    ---
    title: add_days
    tags: date,intermediate
    firstSeen: 2020-10-28T16:19:04+02:00
    lastUpdated: 2020-10-28T16:19:04+02:00
    ---
    
    sudo sed -i '/title:/d' ./*output.md
    sudo sed -i '/firstSeen/d' ./*output.md
    sudo sed -i '/lastUpdated/d' ./*output.md
    sudo sed -i '/tags:/d' ./*output.md
    
    sudo sed -i '/badstring/d' ./*
    
    sudo sed -i '/stargazers/d' ./repo.txt
    sudo sed -i '/node_modules/d' ./index.html
    sudo sed -i '/right\.html/d' ./index.html
    sudo sed -i '/right\.html/d' ./right.html

    22. Zip directory excluding .git and node_modules all the way down (Linux)

    Description:

    Notes:

    code:
    #!/bin/bashTSTAMP=`date '+%Y%m%d-%H%M%S'`zip -r $1.$TSTAMP.zip $1 -x "**.git/*" -x "**node_modules/*" `shift; echo $@;`printf "\nCreated: $1.$TSTAMP.zip\n"# usage:# - zipdir thedir# - zip thedir -x "**anotherexcludedsubdir/*"    (important the double quotes to prevent glob expansion)# if in windows/git-bash, add 'zip' command this way:# https://stackoverflow.com/a/55749636/1482990

    23. Delete files containing a certain string:

    Description:

    Notes:

    code:
    find . | xargs grep -l www.redhat.com | awk '{print "rm "$1}' > doit.sh
    vi doit.sh // check for murphy and his law
    source doit.sh

    24.

    Description:

    Notes:

    code:
    #!/bin/sh# find ./ | grep -i "\.*$" >filesfind ./ | sed -E -e 's/([^ ]+[ ]+){8}//' | grep -i "\.*$">files
    listing="files"out=""html="sitemap.html"out="basename $out.html"html="sitemap.html"cmd() {echo '  <!DOCTYPE html>'echo '<html>'echo '<head>'echo '  <meta http-equiv="Content-Type" content="text/html">'echo '  <meta name="Author" content="Bryan Guner">'echo '<link rel="stylesheet" href="./assets/prism.css">'echo ' <link rel="stylesheet" href="./assets/style.css">'echo ' <script async defer src="./assets/prism.js">
    </script>'echo "  <title> directory </title>"echo '<link rel="stylesheet" href="https://cdn.jsdelivr.net/gh/bgoonz/GIT-CDN-FILES/mdn-article.css">'echo '<link rel="stylesheet" href="https://cdn.jsdelivr.net/gh/bgoonz/GIT-CDN-FILES/markdown-to-html-style.css">'echo ""echo '<style>'echo '    a {'echo '      color: black;'echo '    }'echo ''echo '    li {'echo '      border: 1px solid black !important;'echo '      font-size: 20px;'echo '      letter-spacing: 0px;'echo '      font-weight: 700;'echo '      line-height: 16px;'echo '      text-decoration: none !important;'echo '      text-transform: uppercase;'echo '      background: #194ccdaf !important;'echo '      color: black !important;'echo '      border: none;'echo '      cursor: pointer;'echo '      justify-content: center;'echo '      padding: 30px 60px;'echo '      height: 48px;'echo '      text-align: center;'echo '      white-space: normal;'echo '      border-radius: 10px;'echo '      min-width: 45em;'echo '      padding: 1.2em 1em 0;'echo '      box-shadow: 0 0 5px;'echo '      margin: 1em;'echo '      display: grid;'echo '      -webkit-border-radius: 10px;'echo '      -moz-border-radius: 10px;'echo '      -ms-border-radius: 10px;'echo '      -o-border-radius: 10px;'echo '    }'echo '  </style>'echo '</head>'echo '<body>'echo ""# continue with the HTML stuffecho ""echo ""echo "<ul>"awk '{print "<li>
    <a href=\""$1"\">",$1,"&nbsp;</a>
    </li>"}' $listing# awk '{print "<li>"};# 	{print " <a href=\""$1"\">",$1,"</a></li>&nbsp;"}' \ $listing
    
      echo ""
    
      echo "</ul>"echo "</body>"echo "</html>"}
    
    cmd $listing --sort=extension >>$html

    25. Index of Iframes

    Description: Creates an index.html file that contains all the files in the working directory or any of it's sub folders as iframes instead of anchor tags.

    Notes: Useful Follow up Code:

    code:
    #!/bin/sh# find ./ | grep -i "\.*$" >filesfind ./ | sed -E -e 's/([^ ]+[ ]+){8}//' | grep -i "\.*$">files
    listing="files"out=""html="index.html"out="basename $out.html"html="index.html"cmd() {echo '  <!DOCTYPE html>'echo '<html>'echo '<head>'echo '  <meta http-equiv="Content-Type" content="text/html">'echo '  <meta name="Author" content="Bryan Guner">'echo '<link rel="stylesheet" href="./assets/prism.css">'echo ' <link rel="stylesheet" href="./assets/style.css">'echo ' <script async defer src="./assets/prism.js">
    </script>'echo "  <title> directory </title>"echo ""echo '<style>'echo '    a {'echo '      color: black;'echo '    }'echo ''echo '    li {'echo '      border: 1px solid black !important;'echo '      font-size: 20px;'echo '      letter-spacing: 0px;'echo '      font-weight: 700;'echo '      line-height: 16px;'echo '      text-decoration: none !important;'echo '      text-transform: uppercase;'echo '      background: #194ccdaf !important;'echo '      color: black !important;'echo '      border: none;'echo '      cursor: pointer;'echo '      justify-content: center;'echo '      padding: 30px 60px;'echo '      height: 48px;'echo '      text-align: center;'echo '      white-space: normal;'echo '      border-radius: 10px;'echo '      min-width: 45em;'echo '      padding: 1.2em 1em 0;'echo '      box-shadow: 0 0 5px;'echo '      margin: 1em;'echo '      display: grid;'echo '      -webkit-border-radius: 10px;'echo '      -moz-border-radius: 10px;'echo '      -ms-border-radius: 10px;'echo '      -o-border-radius: 10px;'echo '    }'echo '  </style>'echo '</head>'echo '<body>'echo ""# continue with the HTML stuffecho ""echo ""echo "<ul>"awk '{print "<iframe style="resize:both; overflow:scroll;"  sandbox="allow-scripts" style="resize:both; overflow:scroll;"    src=\""$1"\">","</iframe>
    <br>"}' $listing# awk '{print "<li>"};# 	{print " <a href=\""$1"\">",$1,"</a></li>&nbsp;"}' \ $listing
    
      echo ""
    
      echo "</ul>"echo "</body>"echo "</html>"}
    
    cmd $listing --sort=extension >>$html

    26. Filter Corrupted Git Repo For Troublesome File:

    Description:

    Notes:

    code:
    git filter-branch --index-filter 'git rm -r --cached --ignore-unmatch assets/_index.html' HEAD

    27. OVERWRITE LOCAL CHANGES:

    Description:

    Important: If you have any local changes, they will be lost. With or without --hard option, any local commits that haven't been pushed will be lost.[*] If you have any files that are not tracked by Git (e.g. uploaded user content), these files will not be affected.

    Notes: First, run a fetch to update all origin/ refs to latest:

    code:
    git fetch --all# Backup your current branch:git branch backup-master
    # Then, you have two options:git reset --hard origin/master
    # OR If you are on some other branch:git reset --hard origin/<branch_name># Explanation:# git fetch downloads the latest from remote without trying to merge or rebase anything.# Then the git reset resets the master branch to what you just fetched. The --hard option changes all the files in your working tree to match the files in origin/mastergit fetch --allgit reset --hard origin/master

    28. Remove Submodules:

    Description: To remove a submodule you need to:

    Notes:

    Delete the relevant section from the .gitmodules file. Stage the .gitmodules changes git add .gitmodules Delete the relevant section from .git/config. Run git rm --cached pathtosubmodule (no trailing slash). Run rm -rf .git/modules/pathtosubmodule (no trailing slash). Commit git commit -m "Removed submodule " Delete the now untracked submodule files rm -rf pathtosubmodule

    code:
    git submodule deinit

    29. GET GISTS

    Description:

    Notes:

    code:
    sudo apt install wgetwget -q -O - https://api.github.com/users/bgoonz/gists | grep raw_url | awk -F\" '{print $4}' | xargs -n3 wgetwget -q -O - https://api.github.com/users/amitness/gists | grep raw_url | awk -F\" '{print $4}' | xargs -n3 wgetwget -q -O - https://api.github.com/users/drodsou/gists | grep raw_url | awk -F\" '{print $4}' | xargs -n1 wgetwget -q -O - https://api.github.com/users/thomasmb/gists | grep raw_url | awk -F\" '{print $4}' | xargs -n1 wget

    30. Remove Remote OriginL

    Description:

    Notes:

    code:
    git remote remove origin

    31. just clone .git folder:

    Description:

    Notes:

    code:
    git clone --bare --branch=master --single-branch https://github.com/bgoonz/My-Web-Dev-Archive.git

    32. Undo recent pull request:

    Description:

    Notes:

    code:
    git reset --hard master@{"10 minutes ago"}

    33. Lebab

    Description: ES5 --> ES6

    Notes:

    code:
    # Safe:
    
     lebab --replace ./ --transform arrow
     lebab --replace ./ --transform arrow-return
     lebab --replace ./ --transform for-of
     lebab --replace ./ --transform for-each
     lebab --replace ./ --transform arg-rest
     lebab --replace ./ --transform arg-spread
     lebab --replace ./ --transform obj-method
     lebab --replace ./ --transform obj-shorthand
     lebab --replace ./ --transform multi-var
    
    # ALL:
    
    lebab --replace ./ --transform obj-method
    lebab --replace ./ --transform class
    lebab --replace ./ --transform arrow
    lebab --replace ./ --transform let
    lebab --replace ./ --transform arg-spread
    lebab --replace ./ --transform arg-rest
    lebab --replace ./ --transform for-each
    lebab --replace ./ --transform for-of
    lebab --replace ./ --transform commonjs
    lebab --replace ./ --transform exponent
    lebab --replace ./ --transform multi-var
    lebab --replace ./ --transform template
    lebab --replace ./ --transform default-param
    lebab --replace ./ --transform  destruct-param
    lebab --replace ./ --transform includes
    lebab --replace ./ --transform obj-method
    lebab --replace ./ --transform class
    lebab --replace ./ --transform arrow
    lebab --replace ./ --transform arg-spread
    lebab --replace ./ --transform arg-rest
    lebab --replace ./ --transform for-each
    lebab --replace ./ --transform for-of
    lebab --replace ./ --transform commonjs
    lebab --replace ./ --transform exponent
    lebab --replace ./ --transform multi-var
    lebab --replace ./ --transform template
    lebab --replace ./ --transform default-param
    lebab --replace ./ --transform  destruct-param
    lebab --replace ./ --transform includes

    34. Troubleshoot Ubuntu Input/Output Error

    Description: Open Powershell as Administrator...

    Notes:

    code:
     wsl.exe --shutdown
    
     Get-Service LxssManager | Restart-Service

    35. Export Medium as Markdown

    Description:

    Notes:

    code:
    npm i mediumexporter -g
    
    mediumexporter https://medium.com/codex/fundamental-data-structures-in-javascript-8f9f709c15b4 >ds.md

    36. Delete files in violation of a given size range (100MB for git)

    Description:

    Notes:

    code:
    find . -size +75M -a -print -a -exec rm -f {} \;find . -size +98M -a -print -a -exec rm -f {} \;

    37. download all links of given file type

    Description:

    Notes:

    code:
    wget -r -A.pdf https://overapi.com/git

    38. Kill all node processes

    Description:

    Notes:

    code:
    killall -s KILL node

    39. Remove string from file names recursively

    Description: In the example below I am using this command to remove the string "-master" from all file names in the working directory and all of it's sub directories.

    code:
    find <mydir> -type f -exec sed -i 's/<string1>/<string2>/g' {} +
    
    find . -type f -exec rename 's/-master//g' {} +

    Notes: The same could be done for folder names by changing the -type f flag (for file) to a -type d flag (for directory)

    find <mydir> -type d -exec sed -i 's/<string1>/<string2>/g' {} +
    
    find . -type d -exec rename 's/-master//g' {} +

    40. Remove spaces from file and folder names recursively

    Description: replaces spaces in file and folder names with an _ underscore

    Notes: need to run sudo apt install rename to use this command

    code:
    find . -name "* *" -type d | rename 's/ /_/g'find . -name "* *" -type f | rename 's/ /_/g'

    41. Zip Each subdirectories in a given directory into their own zip file

    Description:

    Notes:

    code:
    for i in */; do zip -r "${i%/}.zip" "$i"; done

    42.

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    91. Unzip PowerShell

    Description:

    Notes:

    code:
    PARAM (
        [string] $ZipFilesPath = "./",
        [string] $UnzipPath = "./RESULT"
    )
    
    $Shell = New-Object -com Shell.Application
    $Location = $Shell.NameSpace($UnzipPath)
    
    $ZipFiles = Get-Childitem $ZipFilesPath -Recurse -Include *.ZIP
    
    $progress = 1
    foreach ($ZipFile in $ZipFiles) {
        Write-Progress -Activity "Unzipping to $($UnzipPath)" -PercentComplete (($progress / ($ZipFiles.Count + 1)) * 100) -CurrentOperation $ZipFile.FullName -Status "File $($Progress) of $($ZipFiles.Count)"
        $ZipFolder = $Shell.NameSpace($ZipFile.fullname)
    
        $Location.Copyhere($ZipFolder.items(), 1040) # 1040 - No msgboxes to the user - https://msdn.microsoft.com/library/bb787866%28VS.85%29.aspx
        $progress++
    }

    92. return to bash from zsh

    Description:

    Notes:

    code:
     sudo apt --purge remove zsh

    93. Symbolic Link

    Description: to working directory

    Notes:

    code:
    ln -s "$(pwd)" ~/NameOfLink
    
    ln -s "$(pwd)" ~/Downloads

    94. auto generate readme

    Description: rename existing readme to blueprint.md

    Notes:

    code:
    npx @appnest/readme generate

    95. Log into postgres:

    Description:

    Notes:

    code:
    sudo -u postgres psql

    96. URL To Subscribe To YouTube Channel

    Description:

    Notes:

    code:
    https://www.youtube.com/channel/UC1HDa0wWnIKUf-b4yY9JecQ?sub_confirmation=1

    97. Embed Repl.it In Medium Post:

    code:
    https://repl.it/@bgoonz/Data-Structures-Algos-Codebase?lite=true&amp;referrer=https%3A%2F%2Fbryanguner.medium.com
    
    https://repl.it/@bgoonz/node-db1-project?lite=true&amp;referrer=https%3A%2F%2Fbryanguner.medium.com
    
    https://repl.it/@bgoonz/interview-prac?lite=true&amp;referrer=https%3A%2F%2Fbryanguner.medium.com
    
    https://repl.it/@bgoonz/Database-Prac?lite=true&amp;referrer=https%3A%2F%2Fbryanguner.medium.com

    98.

    Description:

    Notes:

    code:
    find . -name *right.html  -type f -exec sed -i 's/target="_parent"//g' {} +
    
    find . -name *right.html  -type f -exec sed -i 's/target="_parent"//g' {} +

    99. Cheat Sheet

    Description:

    Notes:

    code:
    #!/bin/bash# SHORTCUTS and HISTORY
    
    
    CTRL+A  # move to beginning of line
    CTRL+B  # moves backward one character
    CTRL+C  # halts the current command
    CTRL+D  # deletes one character backward or logs out of current session, similar to exit
    CTRL+E  # moves to end of line
    CTRL+F  # moves forward one character
    CTRL+G  # aborts the current editing command and ring the terminal bell
    CTRL+H  # deletes one character under cursor (same as DELETE)
    CTRL+J  # same as RETURN
    CTRL+K  # deletes (kill) forward to end of line
    CTRL+L  # clears screen and redisplay the line
    CTRL+M  # same as RETURN
    CTRL+N  # next line in command history
    CTRL+O  # same as RETURN, then displays next line in history file
    CTRL+P  # previous line in command history
    CTRL+Q  # resumes suspended shell output
    CTRL+R  # searches backward
    CTRL+S  # searches forward or suspends shell output
    CTRL+T  # transposes two characters
    CTRL+U  # kills backward from point to the beginning of line
    CTRL+V  # makes the next character typed verbatim
    CTRL+W  # kills the word behind the cursor
    CTRL+X  # lists the possible filename completions of the current word
    CTRL+Y  # retrieves (yank) last item killed
    CTRL+Z  # stops the current command, resume with fg in the foreground or bg in the background
    
    ALT+B   # moves backward one word
    ALT+D   # deletes next word
    ALT+F   # moves forward one word
    ALT+H   # deletes one character backward
    ALT+T   # transposes two words
    ALT+.   # pastes last word from the last command. Pressing it repeatedly traverses through command history.
    ALT+U   # capitalizes every character from the current cursor position to the end of the word
    ALT+L   # uncapitalizes every character from the current cursor position to the end of the word
    ALT+C   # capitalizes the letter under the cursor. The cursor then moves to the end of the word.
    ALT+R   # reverts any changes to a command you've pulled from your history if you've edited it.
    ALT+?   # list possible completions to what is typed
    ALT+^   # expand line to most recent match from history
    
    CTRL+X then (   # start recording a keyboard macro
    CTRL+X then )   # finish recording keyboard macro
    CTRL+X then E   # recall last recorded keyboard macro
    CTRL+X then CTRL+E   # invoke text editor (specified by $EDITOR) on current command line then execute resultes as shell commands
    
    BACKSPACE  # deletes one character backward
    DELETE     # deletes one character under cursorhistory   # shows command line history!!        # repeats the last command!<n>      # refers to command line 'n'!<string> # refers to command starting with 'string'exit      # logs out of current session# BASH BASICSenv                 # displays all environment variablesecho $SHELL         # displays the shell you're usingecho $BASH_VERSION  # displays bash versionbash                # if you want to use bash (type exit to go back to your previously opened shell)whereis bash        # locates the binary, source and manual-page for a commandwhich bash          # finds out which program is executed as 'bash' (default: /bin/bash, can change across environments)clear               # clears content on window (hide displayed lines)# FILE COMMANDSls                            # lists your files in current directory, ls <dir> to print files in a specific directoryls -l                         # lists your files in 'long format', which contains the exact size of the file, who owns the file and who has the right to look at it, and when it was last modifiedls -a                         # lists all files in 'long format', including hidden files (name beginning with '.')ln -s <filename> <link>       # creates symbolic link to file
    readlink <filename>           # shows where a symbolic links points to
    tree                          # show directories and subdirectories in easilly readable file treemc                            # terminal file explorer (alternative to ncdu)touch <filename>              # creates or updates (edit) your file
    mktemp -t <filename>            # make a temp file in /tmp/ which is deleted at next boot (-d to make directory)cat <filename>                # prints file raw content (will not be interpreted)
    any_command > <filename>      # '>' is used to perform redirections, it will set any_command's stdout to file instead of "real stdout" (generally /dev/stdout)more <filename>               # shows the first part of a file (move with space and type q to quit)head <filename>               # outputs the first lines of file (default: 10 lines)tail <filename>               # outputs the last lines of file (useful with -f option) (default: 10 lines)vim <filename>                # opens a file in VIM (VI iMproved) text editor, will create it if it doesn't existmv <filename1> <dest>         # moves a file to destination, behavior will change based on 'dest' type (dir: file is placed into dir; file: file will replace dest (tip: useful for renaming))cp <filename1> <dest>         # copies a filerm <filename>                 # removes a filefind . -name <name> <type>    # searches for a file or a directory in the current directory and all its sub-directories by its namediff <filename1> <filename2>  # compares files, and shows where they differwc <filename>                 # tells you how many lines, words and characters there are in a file. Use -lwc (lines, word, character) to ouput only 1 of those informationssort <filename>               # sorts the contents of a text file line by line in alphabetical order, use -n for numeric sort and -r for reversing order.sort -t -k <filename>         # sorts the contents on specific sort key field starting from 1, using the field separator t.rev                           # reverse string characters (hello becomes olleh)chmod -options <filename>     # lets you change the read, write, and execute permissions on your files (more infos: SUID, GUID)gzip <filename>               # compresses files using gzip algorithm
    gunzip <filename>             # uncompresses files compressed by gzip
    gzcat <filename>              # lets you look at gzipped file without actually having to gunzip itlpr <filename>                # prints the file
    lpq                           # checks out the printer queuelprm <jobnumber>              # removes something from the printer queue
    genscript                     # converts plain text files into postscript for printing and gives you some options for formatting
    dvips <filename>              # prints .dvi files (i.e. files produced by LaTeX)grep <pattern> <filenames>    # looks for the string in the filesgrep -r <pattern> <dir>       # search recursively for pattern in directoryhead -n file_name | tail +n   # Print nth line from file.head -y lines.txt | tail +x   # want to display all the lines from x to y. This includes the xth and yth lines.# DIRECTORY COMMANDSmkdir <dirname>               # makes a new directoryrmdir <dirname>               # remove an empty directoryrmdir -rf <dirname>           # remove a non-empty directorymv <dir1> <dir2>              # rename a directory from <dir1> to <dir2>cd                            # changes to homecd ..                         # changes to the parent directorycd <dirname>                  # changes directorycp -r <dir1> <dir2>           # copy <dir1> into <dir2> including sub-directoriespwd                           # tells you where you currently arecd ~                          # changes to home.cd -                        # changes to previous working directory# SSH, SYSTEM INFO & NETWORK COMMANDSssh user@host            # connects to host as userssh -p <port> user@host  # connects to host on specified port as user
    ssh-copy-id user@host    # adds your ssh key to host for user to enable a keyed or passwordless loginwhoami                   # returns your usernamepasswd                   # lets you change your passwordquota -v                 # shows what your disk quota isdate                     # shows the current date and timecal                      # shows the month's calendaruptime                   # shows current uptime
    w                        # displays whois online
    finger <user>            # displays information about useruname -a                 # shows kernel informationman <command>            # shows the manual for specified commanddf                       # shows disk usagedu <filename>            # shows the disk usage of the files and directories in filename (du -s give only a total)
    last <yourUsername>      # lists your last loginsps -u yourusername       # lists your processeskill <PID>               # kills the processes with the ID you gavekillall <processname>    # kill all processes with the nametop                      # displays your currently active processeslsof                     # lists open filesbg                       # lists stopped or background jobs ; resume a stopped job in the backgroundfg                       # brings the most recent job in the foregroundfg <job>                 # brings job to the foregroundping <host>              # pings host and outputs results
    whois <domain>           # gets whois information for domaindig <domain>             # gets DNS information for domaindig -x <host>            # reverses lookup hostwget <file>              # downloads filetime <command>             # report time consumed by command execution# VARIABLESvarname=value                # defines a variablevarname=value command        # defines a variable to be in the environment of a particular subprocessecho $varname                # checks a variable's valueecho $$                      # prints process ID of the current shellecho $!                      # prints process ID of the most recently invoked background jobecho $?                      # displays the exit status of the last commandread <varname>               # reads a string from the input and assigns it to a variableread -p "prompt" <varname>   # same as above but outputs a prompt to ask user for valuecolumn -t <filename>         # display info in pretty columns (often used with pipe)let <varname> = <equation>   # performs mathematical calculation using operators like +, -, *, /, %export VARNAME=value         # defines an environment variable (will be available in subprocesses)
    
    array[0]=valA                # how to define an array
    array[1]=valB
    array[2]=valC
    array=([2]=valC [0]=valA [1]=valB)  # another wayarray=(valA valB valC)              # and another${array[i]}                  # displays array's value for this index. If no index is supplied, array element 0 is assumed${#array[i]}                 # to find out the length of any element in the array${#array[@]}                 # to find out how many values there are in the arraydeclare -a                   # the variables are treated as arraysdeclare -f                   # uses function names onlydeclare -F                   # displays function names without definitionsdeclare -i                   # the variables are treated as integersdeclare -r                   # makes the variables read-onlydeclare -x                   # marks the variables for export via the environment${varname:-word}             # if varname exists and isn't null, return its value; otherwise return word${varname:word}              # if varname exists and isn't null, return its value; otherwise return word${varname:=word}             # if varname exists and isn't null, return its value; otherwise set it word and then return its value${varname:?message}          # if varname exists and isn't null, return its value; otherwise print varname, followed by message and abort the current command or script${varname:+word}             # if varname exists and isn't null, return word; otherwise return null${varname:offset:length}     # performs substring expansion. It returns the substring of $varname starting at offset and up to length characters${variable#pattern}          # if the pattern matches the beginning of the variable's value, delete the shortest part that matches and return the rest${variable##pattern}         # if the pattern matches the beginning of the variable's value, delete the longest part that matches and return the rest${variable%pattern}          # if the pattern matches the end of the variable's value, delete the shortest part that matches and return the rest${variable%%pattern}         # if the pattern matches the end of the variable's value, delete the longest part that matches and return the rest${variable/pattern/string}   # the longest match to pattern in variable is replaced by string. Only the first match is replaced${variable//pattern/string}  # the longest match to pattern in variable is replaced by string. All matches are replaced${#varname}                  # returns the length of the value of the variable as a character string
    
    *(patternlist)               # matches zero or more occurrences of the given patterns
    +(patternlist)               # matches one or more occurrences of the given patterns
    ?(patternlist)               # matches zero or one occurrence of the given patterns
    @(patternlist)               # matches exactly one of the given patterns!(patternlist)               # matches anything except one of the given patterns$(UNIX command)              # command substitution: runs the command and returns standard output# FUNCTIONS# The function refers to passed arguments by position (as if they were positional parameters), that is, $1, $2, and so forth.# $@ is equal to "$1" "$2"... "$N", where N is the number of positional parameters. $# holds the number of positional parameters.function functname() {
      shell commands
    }unset -f functname  # deletes a function definitiondeclare -f          # displays all defined functions in your login session# FLOW CONTROLS
    
    
    statement1 && statement2  # and operator
    statement1 || statement2  # or operator-a                        # and operator inside a test conditional expression-o                        # or operator inside a test conditional expression# STRINGS
    
    str1 == str2               # str1 matches str2
    str1 != str2               # str1 does not match str2
    str1 < str2                # str1 is less than str2 (alphabetically)
    str1 > str2                # str1 is greater than str2 (alphabetically)
    str1 \> str2               # str1 is sorted after str2
    str1 \< str2               # str1 is sorted before str2-n str1                    # str1 is not null (has length greater than 0)-z str1                    # str1 is null (has length 0)# FILES-a file                   # file exists or its compilation is successful-d file                   # file exists and is a directory-e file                   # file exists; same -a-f file                   # file exists and is a regular file (i.e., not a directory or other special type of file)-r file                   # you have read permission-s file                   # file exists and is not empty-w file                   # your have write permission-x file                   # you have execute permission on file, or directory search permission if it is a directory-N file                   # file was modified since it was last read-O file                   # you own file-G file                   # file's group ID matches yours (or one of yours, if you are in multiple groups)
    file1 -nt file2           # file1 is newer than file2
    file1 -ot file2           # file1 is older than file2# NUMBERS-lt                       # less than-le                       # less than or equal-eq                       # equal-ge                       # greater than or equal-gt                       # greater than-ne                       # not equalif condition
    then
      statements
    [elif condition
      then statements...][else
      statements]fifor x in {1..10}do
      statements
    donefor name [in list]do
      statements that can use $namedonefor (( initialisation ; ending condition ; update ))do
      statements...
    donecase expression in
      pattern1 )
        statements ;;
      pattern2 )
        statements ;;esacselect name [in list]do
      statements that can use $namedonewhile condition; do
      statements
    doneuntil condition; do
      statements
    done# COMMAND-LINE PROCESSING CYCLE# The default order for command lookup is functions, followed by built-ins, with scripts and executables last.# There are three built-ins that you can use to override this order: `command`, `builtin` and `enable`.command  # removes alias and function lookup. Only built-ins and commands found in the search path are executedbuiltin  # looks up only built-in commands, ignoring functions and commands found in PATHenable   # enables and disables shell built-inseval     # takes arguments and run them through the command-line processing steps all over again# INPUT/OUTPUT REDIRECTORS
    
    
    cmd1|cmd2  # pipe; takes standard output of cmd1 as standard input to cmd2< file     # takes standard input from file> file     # directs standard output to file>> file    # directs standard output to file; append to file if it already exists>|file     # forces standard output to file even if noclobber is set
    n>|file    # forces output to file from file descriptor n even if noclobber is set<> file    # uses file as both standard input and standard output
    n<>file    # uses file as both input and output for file descriptor n
    n>file     # directs file descriptor n to file
    n<file     # takes file descriptor n from file
    n>>file    # directs file description n to file; append to file if it already exists
    n>&        # duplicates standard output to file descriptor n
    n<&        # duplicates standard input from file descriptor n
    n>&m       # file descriptor n is made to be a copy of the output file descriptor
    n<&m       # file descriptor n is made to be a copy of the input file descriptor&>file     # directs standard output and standard error to file<&-      # closes the standard input>&-      # closes the standard output
    n>&-     # closes the ouput from file descriptor n
    n<&-     # closes the input from file descripor n|tee <file># output command to both terminal and a file (-a to append to file)# PROCESS HANDLING# To suspend a job, type CTRL+Z while it is running. You can also suspend a job with CTRL+Y.# This is slightly different from CTRL+Z in that the process is only stopped when it attempts to read input from terminal.# Of course, to interrupt a job, type CTRL+C.
    
    myCommand &  # runs job in the background and prompts back the shelljobs         # lists all jobs (use with -l to see associated PID)fg           # brings a background job into the foregroundfg %+        # brings most recently invoked background jobfg %-      # brings second most recently invoked background jobfg %N        # brings job number Nfg %string   # brings job whose command begins with stringfg %?string  # brings job whose command contains stringkill -l               # returns a list of all signals on the system, by name and numberkill PID              # terminates process with specified PIDkill -s SIGKILL 4500  # sends a signal to force or terminate the processkill -15 913          # Ending PID 913 process with signal 15 (TERM)kill %1               # Where %1 is the number of job as read from 'jobs' command.ps           # prints a line of information about the current running login shell and any processes running under itps -a        # selects all processes with a tty except session leaderstrap cmd sig1 sig2  # executes a command when a signal is received by the scripttrap "" sig1 sig2   # ignores that signalstrap - sig1 sig2    # resets the action taken when the signal is received to the default
    
    disown <PID|JID>    # removes the process from the list of jobswait                # waits until all background jobs have finishedsleep <number>      # wait # of seconds before continuingpv                  # display progress bar for data handling commands. often used with pipe like |pvyes                 # give yes response everytime an input is requested from script/process# TIPS & TRICKS# set an aliascd; nano .bash_profile
    > alias gentlenode='ssh admin@gentlenode.com -p 3404'  # add your alias in .bash_profile# to quickly go to a specific directorycd; nano .bashrc
    > shopt -s cdable_vars
    > export websites="/Users/mac/Documents/websites"source .bashrc
    cd $websites# DEBUGGING SHELL PROGRAMSbash -n scriptname  # don't run commands; check for syntax errors onlyset -o noexec       # alternative (set option in script)bash -v scriptname  # echo commands before running themset -o verbose      # alternative (set option in script)bash -x scriptname  # echo commands after command-line processingset -o xtrace       # alternative (set option in script)trap 'echo $varname' EXIT  # useful when you want to print out the values of variables at the point that your script exitsfunction errtrap {es=$?echo "ERROR line $1: Command exited with status $es."}trap 'errtrap $LINENO' ERR  # is run whenever a command in the surrounding script or function exits with non-zero statusfunction dbgtrap {echo "badvar is $badvar"}trap dbgtrap DEBUG  # causes the trap code to be executed before every statement in a function or script# ...section of code in which the problem occurs...trap - DEBUG  # turn off the DEBUG trapfunction returntrap {echo "A return occurred"}trap returntrap RETURN  # is executed each time a shell function or a script executed with the . or source commands finishes executing# COLORS AND BACKGROUNDS# note: \e or \x1B also work instead of \033# ResetColor_Off='\033[0m' # Text Reset# Regular ColorsBlack='\033[0;30m'  # BlackRed='\033[0;31m'    # RedGreen='\033[0;32m'  # GreenYellow='\033[0;33m' # YellowBlue='\033[0;34m'   # BluePurple='\033[0;35m' # PurpleCyan='\033[0;36m'   # CyanWhite='\033[0;97m'  # White# Additional colorsLGrey='\033[0;37m'  # Ligth GrayDGrey='\033[0;90m'  # Dark GrayLRed='\033[0;91m'   # Ligth RedLGreen='\033[0;92m' # Ligth GreenLYellow='\033[0;93m'# Ligth YellowLBlue='\033[0;94m'  # Ligth BlueLPurple='\033[0;95m'# Light PurpleLCyan='\033[0;96m'  # Ligth Cyan# BoldBBlack='\033[1;30m' # BlackBRed='\033[1;31m'   # RedBGreen='\033[1;32m' # GreenBYellow='\033[1;33m'# YellowBBlue='\033[1;34m'  # BlueBPurple='\033[1;35m'# PurpleBCyan='\033[1;36m'  # CyanBWhite='\033[1;37m' # White# UnderlineUBlack='\033[4;30m' # BlackURed='\033[4;31m'   # RedUGreen='\033[4;32m' # GreenUYellow='\033[4;33m'# YellowUBlue='\033[4;34m'  # BlueUPurple='\033[4;35m'# PurpleUCyan='\033[4;36m'  # CyanUWhite='\033[4;37m' # White# BackgroundOn_Black='\033[40m' # BlackOn_Red='\033[41m'   # RedOn_Green='\033[42m' # GreenOn_Yellow='\033[43m'# YellowOn_Blue='\033[44m'  # BlueOn_Purple='\033[45m'# PurpleOn_Cyan='\033[46m'  # CyanOn_White='\033[47m' # White# Example of usageecho -e "${Green}This is GREEN text${Color_Off} and normal text"echo -e "${Red}${On_White}This is Red test on White background${Color_Off}"# option -e is mandatory, it enable interpretation of backslash escapesprintf "${Red} This is red \n"