Useful Bash Commands
-
Linux
CommandLine
CommandOfTheDay
Bash
Overview
- Shortcuts
- Clear Terminal
- Run Previous Command With Root/Sudo Privilege
- Run Previous Command With Search/Replace For First Instance
- Run Previous Command With Search/Replace For All The Instance
- Execute Command Without Saving in History
- Paste Last Argument of Most Recent Command
- Paste Selected Argument
- Reset Terminal
- Display Mount Filesystem in Nice Layout
- ASCII Table
- Compare Remote File with Local File
- Decide Which Command Run On Success and Fail
- Execute Command After Every 2 Seconds
- Check Last Command Status
NOTE!: If you feel some commands are missing in this post,
Feel free to add those commands in below comments box.
Shortcuts
/---------------------------------------------------------------------------------------\ | !! Repeat last command | | !char Repeat last command That started with char | | !num Repeat a command by its number in history output | | | | !-n Repeat a command entered n command back | | !?abc Repeat last command that contains (as opposed to ?started with?) abc | \---------------------------------------------------------------------------------------/
/---------------------------------------------------------------\ | UP DOWN Keys Scroll through previous commands | | Ctrl+r Reverse-i-search | \---------------------------------------------------------------/
Clear Terminal
# Linux/Unix OS
$ <CTRL+l>
# MAC OS
# The following keys not just clear screen but also clear Terminal buffer
# After <COMMAND+k> you can't able to view previous buffer
$ <COMMAND+k>Run Previous Command With Root/Sudo Privilege
$ sudo !!Run Previous Command With Search/Replace For First Instance
$ echo "Hello Mitesh, Hello Shah, Hello Visitor"
Hello Mitesh, Hello Shah, Hello Visitor
$ ^Hello^Hi
$ echo "Hi Mitesh, Hello Shah, Hello Visitor"
Hi Mitesh, Hello Shah, Hello VisitorRun Previous Command With Search/Replace For All The Instance
$ echo "Hello Mitesh, Hello Shah, Hello Visitor"
Hello Mitesh, Hello Shah, Hello Visitor
$ !!:gs/Hello/Hi
$ echo "Hi Mitesh, Hi Shah, Hi Visitor"
Hi Mitesh, Hi Shah, Hi VisitorExecute Command Without Saving in History
- Prepending one or more spaces to your command won’t be saved in history.
$ <SPACE><COMMAND>NOTE!: HISTCONTROL=ignorespace will ignore just the commands that begin with a space.
Use HISTCONTROL=ignoreboth if you also want to ignore duplicates.
Paste Last Argument of Most Recent Command
/-----------------------------------------------------------------------\ | Esc . The escape key followed by a period. | | Alt+. Hold down alt key while pressing the period. | | !$ Only valid for last argument | \-----------------------------------------------------------------------/
$ cp -v index.html /home/mitesh/shah/edytk.github.io/index.html
# Using ALT Dot
$ cd <ALT+.>
$ cd /home/mitesh/shah/edytk.github.io/index.html
# Using Esc Dot
$ cd <ESC+.>
$ cd /home/mitesh/shah/edytk.github.io/index.html
# Using !$
$ cd !$
$ cd /home/mitesh/shah/edytk.github.io/index.htmlPaste Selected Argument
- This comes in handy when you’ve written a long command with multiple arguments and you want to reuse one of them.
# Use Only 3rd Argument
$ echo a b c d e
a b c d e
$ echo !:3
echo c
c
# Used 1-3 Argument Only
$ echo a b c d e
a b c d e
$ echo !:1-3
echo a b c
a b c
# If you leave off the first digit and just start with `!:-`
# then you'll include argument 0, which is the previous command.
$ echo a b c d e
a b c d e
$ echo !:-3
echo echo a b c
echo a b cReset Terminal
- Sometime we send binary output to the terminal, Which make terminal not useable.
- The
resetcommand reset your terminal, Note that when you type reset its won’t properly echo back on terminal.
$ resetDisplay Mount Filesystem in Nice Layout
$ mount | column -t
/dev/root on / type ext4 (rw,relatime,errors=remount-ro,data=ordered)
devtmpfs on /dev type devtmpfs (rw,relatime,size=4037132k,nr_inodes=1009283,mode=755)
none on /dev/pts type devpts (rw,nosuid,noexec,relatime,mode=600)
none on /proc type proc (rw,nosuid,nodev,noexec,relatime)
none on /sys type sysfs (rw,nosuid,nodev,noexec,relatime)
none on /proc/sys/fs/binfmt_misc type binfmt_misc (rw,nosuid,nodev,noexec,relatime)
none on /sys/fs/fuse/connections type fusectl (rw,relatime)
none on /sys/kernel/security type securityfs (rw,relatime)
none on /run type tmpfs (rw,nosuid,noexec,relatime,size=807520k,mode=755)
none on /run/lock type tmpfs (rw,nosuid,nodev,noexec,relatime,size=5120k)
none on /run/shm type tmpfs (rw,nosuid,nodev,relatime)ASCII Table
$ man asciiCompare Remote File with Local File
$ ssh USERNAME@HOSTNAME cat /path/to/remotefile | diff /path/to/localfile -Decide Which Command Run On Success and Fail
$ cal && echo "Right Command" || echo "Wrong Command"
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Right Command
$ call && echo "Right Command" || echo "Wrong Command"
No command 'call' found, did you mean:
Command 'wall' from package 'bsdutils' (main)
Command 'calc' from package 'apcalc' (universe)
Command 'cal' from package 'bsdmainutils' (main)
call: command not found
Wrong CommandExecute Command After Every 2 Seconds
$ watch -d df -h
Every 2.0s: df -h Tue Jul 7 13:52:39 2015
Filesystem Size Used Avail Use% Mounted on
rootfs 500G 250G 250G 50% /
/dev/root 500G 250G 250G 50% /
devtmpfs 3.9G 4.0K 3.9G 1% /dev
none 789M 165M 625M 21% /run
none 5.0M 0 5.0M 0% /run/lock
none 3.9G 0 3.9G 0% /run/shmCheck Last Command Status
- If command run Successfully then exit status is zero
- If command doesn’t run Successfully then exit status is non-zero
$ cal ; echo $?
$ call ; echo $?Newsletter
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