Bash Cheat Sheet

!!            # Run the last commandtouch foo.sh
chmod +x !$   # !$ is the last argument of the last command i.e. foo.sh

pwd                       # Print current directory pathls                        # List directoriesls -a|--all               # List directories including hiddenls -l                     # List directories in long formls -l -h|--human-readable # List directories in long form with human readable sizesls -t                     # List directories by modification time, newest firststat foo.txt              # List size, created and modified timestamps for a filestat foo                  # List size, created and modified timestamps for a directory
tree                      # List directory and file tree
tree -a                   # List directory and file tree including hidden
tree -d                   # List directory treecd foo                    # Go to foo sub-directorycd                        # Go to home directorycd ~                      # Go to home directorycd -                      # Go to last directorypushd foo                 # Go to foo sub-directory and add previous directory to stackpopd                      # Go back to directory in stack saved by `pushd`

mkdir foo                        # Create a directorymkdir foo bar                    # Create multiple directoriesmkdir -p|--parents foo/bar       # Create nested directorymkdir -p|--parents {foo,bar}/baz # Create multiple nested directories

mktemp -d|--directory            # Create a temporary directory

cp -R|--recursive foo bar                               # Copy directorymv foo bar                                              # Move directoryrsync -z|--compress -v|--verbose /foo /bar              # Copy directory, overwrites destinationrsync -a|--archive -z|--compress -v|--verbose /foo /bar # Copy directory, without overwriting destinationrsync -avz /foo username@hostname:/bar                  # Copy local directory to remote directoryrsync -avz username@hostname:/foo /bar                  # Copy remote directory to local directory

rmdir foo                        # Delete non-empty directoryrm -r|--recursive foo            # Delete directory including contentsrm -r|--recursive -f|--force foo # Delete directory including contents, ignore nonexistent files and never prompt

touch foo.txt          # Create file or update existing files modified timestamptouch foo.txt bar.txt  # Create multiple filestouch {foo,bar}.txt    # Create multiple filestouch test{1..3}       # Create test1, test2 and test3 filestouch test{a..c}       # Create testa, testb and testc files

mktemp                 # Create a temporary file

echo "foo" > bar.txt       # Overwrite file with contentecho "foo" >> bar.txt      # Append to file with contentls exists 1> stdout.txt    # Redirect the standard output to a filels noexist 2> stderror.txt # Redirect the standard error output to a filels 2>&1 out.txt            # Redirect standard output and error to a filels > /dev/null             # Discard standard output and errorread foo                   # Read from standard input and write to the variable foo

cp foo.txt bar.txt                                # Copy filemv foo.txt bar.txt                                # Move filersync -z|--compress -v|--verbose /foo.txt /bar    # Copy file quickly if not changedrsync z|--compress -v|--verbose /foo.txt /bar.txt # Copy and rename file quickly if not changed

rm foo.txt            # Delete filerm -f|--force foo.txt # Delete file, ignore nonexistent files and never prompt

cat foo.txt            # Print all contentsless foo.txt           # Print some contents at a time (g - go to top of file, SHIFT+g, go to bottom of file, /foo to search for 'foo')head foo.txt           # Print top 10 lines of filetail foo.txt           # Print bottom 10 lines of fileopen foo.txt           # Open file in the default editorwc foo.txt             # List number of lines words and characters in the file

ls -l /foo.sh            # List file permissionschmod +100 foo.sh        # Add 1 to the user permissionchmod -100 foo.sh        # Subtract 1 from the user permissionchmod u+x foo.sh         # Give the user execute permissionchmod g+x foo.sh         # Give the group execute permissionchmod u-x,g-x foo.sh     # Take away the user and group execute permissionchmod u+x,g+x,o+x foo.sh # Give everybody execute permissionchmod a+x foo.sh         # Give everybody execute permissionchmod +x foo.sh          # Give everybody execute permission

type wget                                  # Find the binarywhich wget                                 # Find the binarywhereis wget                               # Find the binary, source, and manual page files

updatedb                                   # Update the indexlocate foo.txt                             # Find a filelocate --ignore-case                       # Find a file and ignore caselocate f*.txt                              # Find a text file starting with 'f'

find /path -name foo.txt                   # Find a filefind /path -iname foo.txt                  # Find a file with case insensitive searchfind /path -name "*.txt"                   # Find all text filesfind /path -name foo.txt -delete           # Find a file and delete itfind /path -name "*.png" -exec pngquant {} # Find all .png files and execute pngquant on itfind /path -type f -name foo.txt           # Find a filefind /path -type d -name foo               # Find a directoryfind /path -type l -name foo.txt           # Find a symbolic linkfind /path -type f -mtime +30              # Find files that haven't been modified in 30 daysfind /path -type f -mtime +30 -delete      # Delete files that haven't been modified in 30 days

grep 'foo' /bar.txt                         # Search for 'foo' in file 'bar.txt'grep 'foo' /bar -r|--recursive              # Search for 'foo' in directory 'bar'grep 'foo' /bar -R|--dereference-recursive  # Search for 'foo' in directory 'bar' and follow symbolic linksgrep 'foo' /bar -l|--files-with-matches     # Show only files that matchgrep 'foo' /bar -L|--files-without-match    # Show only files that don't matchgrep 'Foo' /bar -i|--ignore-case            # Case insensitive searchgrep 'foo' /bar -x|--line-regexp            # Match the entire linegrep 'foo' /bar -C|--context 1              # Add N line of context above and below each search resultgrep 'foo' /bar -v|--invert-match           # Show only lines that don't matchgrep 'foo' /bar -c|--count                  # Count the number lines that matchgrep 'foo' /bar -n|--line-number            # Add line numbersgrep 'foo' /bar --colour                    # Add colour to outputgrep 'foo\|bar' /baz -R                     # Search for 'foo' or 'bar' in directory 'baz'grep --extended-regexp|-E 'foo|bar' /baz -R # Use regular expressionsegrep 'foo|bar' /baz -R                     # Use regular expressions

sed 's/fox/bear/g' foo.txt               # Replace fox with bear in foo.txt and output to consolesed 's/fox/bear/gi' foo.txt              # Replace fox (case insensitive) with bear in foo.txt and output to consolesed 's/red fox/blue bear/g' foo.txt      # Replace red with blue and fox with bear in foo.txt and output to consolesed 's/fox/bear/g' foo.txt > bar.txt     # Replace fox with bear in foo.txt and save in bar.txtsed 's/fox/bear/g' foo.txt -i|--in-place # Replace fox with bear and overwrite foo.txt

ln -s|--symbolic foo bar            # Create a link 'bar' to the 'foo' folderln -s|--symbolic -f|--force foo bar # Overwrite an existing symbolic link 'bar'ls -l                               # Show where symbolic links are pointing

zip foo.zip /bar.txt                # Compress bar.txt into foo.zipzip foo.zip /bar.txt /baz.txt       # Compress bar.txt and baz.txt into foo.zipzip foo.zip /{bar,baz}.txt          # Compress bar.txt and baz.txt into foo.zipzip -r|--recurse-paths foo.zip /bar # Compress directory bar into foo.zip

gzip /bar.txt foo.gz           # Compress bar.txt into foo.gz and then delete bar.txtgzip -k|--keep /bar.txt foo.gz # Compress bar.txt into foo.gz

tar -c|--create -z|--gzip -f|--file=foo.tgz /bar.txt /baz.txt # Compress bar.txt and baz.txt into foo.tgztar -c|--create -z|--gzip -f|--file=foo.tgz /{bar,baz}.txt    # Compress bar.txt and baz.txt into foo.tgztar -c|--create -z|--gzip -f|--file=foo.tgz /bar              # Compress directory bar into foo.tgz

unzip foo.zip          # Unzip foo.zip into current directory

gunzip foo.gz           # Unzip foo.gz into current directory and delete foo.gz
gunzip -k|--keep foo.gz # Unzip foo.gz into current directory

tar -x|--extract -z|--gzip -f|--file=foo.tar.gz # Un-compress foo.tar.gz into current directorytar -x|--extract -f|--file=foo.tar              # Un-combine foo.tar into current directory

df                     # List disks, size, used and available spacedf -h|--human-readable # List disks, size, used and available space in a human readable formatdu                     # List current directory, subdirectories and file sizesdu /foo/bar            # List specified directory, subdirectories and file sizesdu -h|--human-readable # List current directory, subdirectories and file sizes in a human readable formatdu -d|--max-depth      # List current directory, subdirectories and file sizes within the max depthdu -d 0                # List current directory size

free                   # Show memory usagefree -h|--human        # Show human readable memory usagefree -h|--human --si   # Show human readable memory usage in power of 1000 instead of 1024free -s|--seconds 5    # Show memory usage and update continuously every five seconds

apt update             # Refreshes repository indexapt search wget        # Search for a packageapt show wget          # List information about the wget packageapt install wget       # Install the wget packageapt remove wget        # Removes the wget packageapt upgrade            # Upgrades all upgradable packages

shutdown                     # Shutdown in 1 minuteshutdown now "Cya later"     # Immediately shut downshutdown +5 "Cya later"      # Shutdown in 5 minutesshutdown --reboot            # Reboot in 1 minuteshutdown -r now "Cya later"  # Immediately rebootshutdown -r +5 "Cya later"   # Reboot in 5 minutesshutdown -c                  # Cancel a shutdown or rebootreboot                       # Reboot nowreboot -f                    # Force a reboot

top                    # List all processes interactivelyhtop                   # List all processes interactivelyps all                 # List all processes
pidof foo              # Return the PID of all foo processes

CTRL+Z                 # Suspend a process running in the foregroundbg                     # Resume a suspended process and run in the backgroundfg                     # Bring the last background process to the foregroundfg 1                   # Bring the background process with the PID to the foregroundsleep 30 &             # Sleep for 30 seconds and move the process into the backgroundjobs                   # List all background jobsjobs -p                # List all background jobs with their PIDlsof                   # List all open files and the process using themlsof -itcp:4000        # Return the process listening on port 4000

nice -n -20 foo        # Change process priority by namerenice 20 PID          # Change process priority by PIDps -o ni PID           # Return the process priority of PID

CTRL+C                 # Kill a process running in the foregroundkill PID               # Shut down process by PID gracefully. Sends TERM signal.kill -9 PID            # Force shut down of process by PID. Sends SIGKILL signal.pkill foo              # Shut down process by name gracefully. Sends TERM signal.pkill -9 foo           # force shut down process by name. Sends SIGKILL signal.killall foo            # Kill all process with the specified name gracefully.

date                   # Print the date and timedate --iso-8601        # Print the ISO8601 datedate --iso-8601=ns     # Print the ISO8601 date and timetime tree              # Time how long the tree command takes to execute

   *      *         *         *           *
Minute, Hour, Day of month, Month, Day of the week

crontab -l                 # List cron tabcrontab -e                 # Edit cron tab in Vimcrontab /path/crontab      # Load cron tab from a filecrontab -l > /path/crontab # Save cron tab to a file

* * * * * foo              # Run foo every minute
*/15 * * * * foo           # Run foo every 15 minutes0 * * * * foo              # Run foo every hour15 6 * * * foo             # Run foo daily at 6:15 AM44 4 * * 5 foo             # Run foo every Friday at 4:44 AM0 0 1 * * foo              # Run foo at midnight on the first of the month0 0 1 1 * foo              # Run foo at midnight on the first of the year

at -l                      # List scheduled tasks
at -c 1                    # Show task with ID 1
at -r 1                    # Remove task with ID 1
at now + 2 minutes         # Create a task in Vim to execute in 2 minutes
at 12:34 PM next month     # Create a task in Vim to execute at 12:34 PM next month
at tomorrow                # Create a task in Vim to execute tomorrow

curl https://example.com                               # Return response bodycurl -i|--include https://example.com                  # Include status code and HTTP headerscurl -L|--location https://example.com                 # Follow redirectscurl -o|--remote-name foo.txt https://example.com      # Output to a text filecurl -H|--header "User-Agent: Foo" https://example.com # Add a HTTP headercurl -X|--request POST -H "Content-Type: application/json" -d|--data '{"foo":"bar"}' https://example.com # POST JSONcurl -X POST -H --data-urlencode foo="bar" http://example.com                           # POST URL Form Encodedwget https://example.com/file.txt .                            # Download a file to the current directorywget -O|--output-document foo.txt https://example.com/file.txt # Output to a file with the specified name

ping example.com            # Send multiple ping requests using the ICMP protocolping -c 10 -i 5 example.com # Make 10 attempts, 5 seconds apartip addr                     # List IP addresses on the systemip route show               # Show IP addresses to routernetstat -i|--interfaces     # List all network interfaces and in/out usagenetstat -l|--listening      # List all open portstraceroute example.com      # List all servers the network traffic goes throughmtr -w|--report-wide example.com                                    # Continually list all servers the network traffic goes throughmtr -r|--report -w|--report-wide -c|--report-cycles 100 example.com # Output a report that lists network traffic 100 times

nmap 0.0.0.0                # Scan for the 1000 most common open ports on localhost
nmap 0.0.0.0 -p1-65535      # Scan for open ports on localhost between 1 and 65535
nmap 192.168.4.3            # Scan for the 1000 most common open ports on a remote IP address
nmap -sP 192.168.1.1/24     # Discover all machines on the network by ping'ing them

host example.com            # Show the IPv4 and IPv6 addressesdig example.com             # Show complete DNS informationcat /etc/resolv.conf        # resolv.conf lists nameservers

lsusb                  # List USB devices
lspci                  # List PCI hardware
lshw                   # List all hardware

tmux             # Start a new session (CTRL-b + d to detach)
tmux ls          # List all sessions
tmux attach -t 0 # Reattach to a sessionscreen           # Start a new session (CTRL-a + d to detach)screen -ls       # List all sessionsscreen -R 31166  # Reattach to a sessionexit             # Exit a session

ssh hostname                 # Connect to hostname using your current user name over the default SSH port 22ssh -i foo.pem hostname      # Connect to hostname using the identity filessh user@hostname            # Connect to hostname using the user over the default SSH port 22ssh user@hostname -p 8765    # Connect to hostname using the user over a custom portssh ssh://user@hostname:8765 # Connect to hostname using the user over a custom port

$ cat ~/.ssh/config
Host name
  User foo
  Hostname 127.0.0.1
  Port 8765
$ ssh name

scp foo.txt ubuntu@hostname:/home/ubuntu # Copy foo.txt into the specified remote directory

# Always run ls after cdfunction cd {builtin cd "$@" && ls}# Prompt user before overwriting any filesalias cp='cp --interactive'alias mv='mv --interactive'alias rm='rm --interactive'# Always show disk usage in a human readable formatalias df='df -h'alias du='du -h'

#!/bin/bashfoo=123                # Initialize variable foo with 123declare -i foo=123     # Initialize an integer foo with 123declare -r foo=123     # Initialize readonly variable foo with 123echo $foo              # Print variable fooecho ${foo}_'bar'      # Print variable foo followed by _barecho ${foo:-'default'} # Print variable foo if it exists otherwise print defaultexport foo             # Make foo available to child processesunset foo              # Make foo unavailable to child processes

#!/bin/bashenv        # List all environment variablesecho $PATH # Print PATH environment variable

#!/bin/bashgreet() {local world = "World"echo "$1 $world"return "$1 $world"}
greet "Hello"greeting=$(greet "Hello")

#!/bin/bashexit 0   # Exit the script successfullyexit 1   # Exit the script unsuccessfullyecho $?  # Print the last exit code

#!/bin/bashif [[$foo = 'bar']]; thenecho 'one'elif [[$foo = 'bar']] || [[$foo = 'baz']]; thenecho 'two'elif [[$foo = 'ban']] && [[$USER = 'bat']]; thenecho 'three'elseecho 'four'fi

#!/bin/bash[[ $USER = 'rehan' ]] && echo 'yes' || echo 'no'

#!/bin/bashdeclare -i counter
counter=10while [$counter -gt 2]; doecho The counter is $countercounter=counter-1
done

#!/bin/bashfor i in {0..10..2}doecho "Index: $i"donefor filename in file1 file2 file3
  doecho "Content: " >> $filenamedonefor filename in *;doecho "Content: " >> $filenamedone

#!/bin/bashecho "What's the weather like tomorrow?"read weather

case $weather in
  sunny | warm ) echo "Nice weather: " $weather;;
  cloudy | cool ) echo "Not bad weather: " $weather;;
  rainy | cold ) echo "Terrible weather: " $weather;;
  * ) echo "Don't understand";;esac