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;});

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

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 -- {} +

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

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

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

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

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

git stash
git pull
git stash pop

sudo npm i prettier -g

prettier --write .

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"' {} \;

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

npm i @bgoonz11/repoutils

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

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' {} +

#!/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

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

////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;});

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

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 '{}' +

sudo sed -i '/\.js/!d' ./*scrap2.md

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' ./*

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

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

#!/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

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

#!/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

#!/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

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

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

git submodule deinit

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

git remote remove origin

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

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

# 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

 wsl.exe --shutdown

 Get-Service LxssManager | Restart-Service

npm i mediumexporter -g

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

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

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

killall -s KILL node

find <mydir> -type f -exec sed -i 's/<string1>/<string2>/g' {} +

find . -type f -exec rename 's/-master//g' {} +

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

find . -type d -exec rename 's/-master//g' {} +

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

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

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++
}

 sudo apt --purge remove zsh

ln -s "$(pwd)" ~/NameOfLink

ln -s "$(pwd)" ~/Downloads

npx @appnest/readme generate

sudo -u postgres psql

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

https://repl.it/@bgoonz/Data-Structures-Algos-Codebase?lite=true&referrer=https%3A%2F%2Fbryanguner.medium.com

https://repl.it/@bgoonz/node-db1-project?lite=true&referrer=https%3A%2F%2Fbryanguner.medium.com

https://repl.it/@bgoonz/interview-prac?lite=true&referrer=https%3A%2F%2Fbryanguner.medium.com

https://repl.it/@bgoonz/Database-Prac?lite=true&referrer=https%3A%2F%2Fbryanguner.medium.com

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' {} +

#!/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"