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!

History
Directories
Files
Searching
Networking
User environment
File system
Date & Time
Processes
Miscellaneous

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.

olekhy/command-line-one-liners

Command line one-liners

Table of Contents

History

Directories

Files

Searching

Networking

User environment

Networking

File system

Date & Time

Processes

Miscellaneous

Who made this?