Command line one-liners

After my article about command line one-liners, many people want to contribute with their own commands. This is the place to do it, pull requests are welcome!

Table of Contents


History

  • Run the last command

    $ !!
    
  • Run the last command as root

    $ sudo !!
    
  • Create a script of the last executed command

    $ echo "!!" > script.sh
    
  • Reuse all parameter of the previous command line

    $ echo cd .
    $ !*
    
  • Run the last command with some argument

    $ echo a b c d e
    $ echo !!:2
    $ echo !!:3-$
    
  • Insert the last argument of the previous command

    $ cp script.sh /usr/bin/
    $ cd !$
    $ cd <ESC> .
    $ cd <ALT> .
    
  • Runs previous command but replacing

    $ echo no typos
    $ ^typos^errors
    
  • Escape any command aliases

    $ alias ls="ls -a"
    $ \ls
    
  • Run a command from the history

    $ history
       ...
       1225  ls -l
       1226  git status
       1227  history
    $ !-3
    $ !1225
    
  • Search the history for the most recent command beginning with text

    $ !text
    
  • Search the history for the most recent command containing text

    $ <ctrl-r>text
    
  • List of commands you use most often

    $ history | awk '{print $2}' | sort | uniq -c | sort -rn | head
    
  • Execute a command without saving it in the history

    $ <space>command
    

Directories

  • Make a directory creating intermediate directories

    $ mkdir -p a/long/directory/path
    
  • Create a directory and change into it

    $ mkdir dir && cd $_
    
  • Change to the previous working directory

    $ cd -
    
  • Jump to a directory. Execute a command in a subshell. Jump back to current directory

    $ (cd /tmp && ls)
    

Files

  • Quickly rename a file

    $ mv filename.{old,new}
    $ mv filename.{png,jpg}
    
  • Create a quick back-up copy of a file

    $ cp file.txt{,.bak}
    
  • Create a simple text file from command line

    $ cat > file.txt
    {your text here}
    {your text here}
    <ctrl-d>
    
  • Create a simple text file from command line or script (EOF is just a token, can be any word)

    $ cat > file.txt << EOF
    {your text here}
    {your text here}
    EOF
    
  • Empty a file from command line (usefull to truncate log file from running processes)

    $ > file.txt
    
  • Empty a file from command line or script

    $ cat /dev/null > file.txt
    
  • Make less behave like tail -f

    $ less +F somelogfile
    
  • Display line numbers in a file

    $ cat -n file
    $ less -N file
    
  • Redirect standard input to a file. Print it to standard output

    $ command | tee file.txt | less
    
      ┌─────────┐  ┌─────────┐  ┌─────────┐
      │ command │─▸│   tee   │─▸│ stdout  │
      └─────────┘  └────┬────┘  └─────────┘
                        │
                        ▾
                  ┌───────────┐
                  │   file    │
                  └───────────┘
    

Searching

  • Search for a string inside all files in the current directory

    $ grep -RnsI --color=auto <pattern> *
    
  • Beyond grep

      _   /|
      \'o.O'
      =(___)=
        U    ack!
    
    $ ack <pattern>
    
  • Recursively remove all empty directories

    $ find . -type d -empty -delete
    

Networking

  • Serve current directory tree at http://$HOSTNAME:8000/

    $ python -m SimpleHTTPServer
    $ ruby -run -e httpd . -p 8000
    
  • Share a file between two computers

    receiver $ nc -l 5566 > data-dump.sql
    sender   $ nc <receiver-ip-address> 5566 < data-dump.sql
    
  • Share a BIG file between two computers and show progress bar

    receiver $ nc -l 5566 > big-file.iso
    sender   $ pv big-file.iso | nc <receiver-ip-address> 5566
    
  • Transfer a folder between two computers

    receiver $ nc -l 5566 | tar -zxv
    sender   $ tar -zcv <folder> | nc -w1 <receiver-ip-address> 5566
    
  • Download an entire website

    $ wget -m -k http://website.com
    

User environment

  • Show PATH in a human-readable way

    $ echo $PATH | tr ':' '\n'
    $ tr ':' '\n' <<< $PATH
    
  • Clear the terminal screen

    $ <ctrl-l>
    $ clear
    
  • Salvage a borked terminal

    $ reset
    
  • Close shell keeping all subprocess running

    $ disown -a && exit
    
  • Run a command immune to hangups

    $ nohup command &
    

Networking

  • Attach screen over ssh

    $ ssh user@host -t screen -r
    
  • Compare a remote file with a local file

    $ ssh user@host cat /path/to/remotefile | diff /path/to/localfile -
    
  • Get your public IP address

    $ curl ifconfig.me
    
  • Set audible alarm when an IP address comes online

    $ ping -a IP_address
    
  • List programs with open ports and connections

    $ lsof -i
    
  • Check which process is listening on a specific port

    $ netstat -nlp | grep 8080
    $ netstat -nlp tcp | grep 8080 (BSD)
    

File system

  • Currently mounted filesystems in nice layout

    $ mount | column -t
    
  • Display free disk space

    $ df -h
    
  • Display disk usage statistics for the current directory

    $ du -sh *
    
  • Display 10 biggest files/folders for the current directory

    $ du -s * | sort -nr | head
    
  • Create a zip archive of a directory

    $ zip -r archive.zip directory
    
  • Extract compressed archive

    $ unzip archive.zip
    
  • Show File System Hierarchy

    $ man hier
    

Date & Time

  • Shutdown the system at a given time

    $ shutdown -h now
    $ shutdown -h 22:49
    
  • Execute a command at a given time

    $ echo "ls -l" | at midnight
    
  • Simple stopwatch

    $ time read
    <ctrl-d>
    
  • Put a console clock in top right corner

    $ while sleep 1;do tput sc;tput cup 0 $(($(tput cols)-29));date;tput rc;done &
    
  • Displays a calendar

    $ cal 12 1984
    
  • What day was yesterday or will it be tomorrow, etc...

    $ date -d yesterday
    $ date -d tomorrow +%Y-%m-%d
    $ date -d "7 days ago" +%Y-%m-%d
    $ date -j -v-1d (BSD)
    

Processes

  • Display the top ten running processes. (Sorted by memory usage)

    $ ps aux | sort -nk +4 | tail
    
  • Kill all Ruby processes

    $ ps aux | grep ruby | awk '{ print $2 }' | xargs kill -9
    $ ps aux | awk '/ruby/ && ! /awk/ { system("kill -9 "$2) }'
    $ pkill -f ruby
    $ killall -9 ruby
    
  • Check which process is modifying a certain directory or file

    $ auditctl -w /path/to/directory -p war
    

    See results

    $ ausearch -f /path/to/directory
    

Miscellaneous

  • 32 bits or 64 bits?

    $ getconf LONG_BIT
    
  • Quick access to the ascii table

    $ man ascii
    
  • Count your commits

    $ git shortlog -sn
    
  • Russian Roulette in Bash (remember kids don't try this at home)

    $ [ $[ $RANDOM % 6 ] == 0 ] && rm -rf / || echo "You live"
    
  • Watch Star Wars via telnet

    $ telnet towel.blinkenlights.nl
    

Who made this?

This was made by Arturo Herrero under the MIT License. Find me on Twitter @ArturoHerrero.