Shell Tips & Tricks
Create A Command Alias
Most of us use 'ls -l' so, will it not be easier to have a smaller command to show us long listing, add the following line to ~/.bashrc
Using it
You may create as many aliases as you want. Please share any interesting aliases you create.
Use Previous Command's Arguments
Running a command with the same arguments used in the previous command, use '!*' to repeat all arguments or '!:2' to use the second argument. '!$' uses the last argument. Let's see a few examples.
Useful Bash Keystrokes
Ctrl+U - Cuts everything to the left
Ctrl+W - Cuts the word to the left
Ctrl+Y - Pastes what's in the buffer
Ctrl+A - Go to beginning of line
Ctrl+E - Go to end of line
Ctrl+R - Search command history
Changing File Extensions
This will change all .html files to html.bak
Run a second command only if the first one is successfull
This is usually used like this 'make && make install' while compiling softwares.
Create A Command Alias
Most of us use 'ls -l' so, will it not be easier to have a smaller command to show us long listing, add the following line to ~/.bashrc
Code:
alias ll='ls -l'
Code:
[root@pradeep ~]# ll total 264 -rw------- 1 root root 1221 May 21 21:57 anaconda-ks.cfg -rw-r--r-- 1 root root 2063 Jul 20 12:21 content_passlimit.txt drwxr-xr-x 2 root root 4096 Jul 20 16:09 dumps -rw-r--r-- 1 root root 35779 May 21 21:56 install.log -rw-r--r-- 1 root root 5142 May 21 21:56 install.log.syslog drwxr-xr-x 7 root root 4096 Jun 24 16:23 json-1.2.0 -rw-r--r-- 1 root root 13286 Mar 15 2006 json-1.2.0.tgz -rw-r--r-- 1 root root 17 Aug 10 13:30 lwp_cookies.dat -rw------- 1 root root 141066 May 29 17:47 mbox -rw-r--r-- 1 root root 11484 Jul 6 13:01 modify_printfile.pl -rw-rw-r-- 1 nagios nagios 4289 Mar 15 2006 package.xml drwxr-xr-x 2 root root 4096 Jul 27 19:29 test drwxr-xr-x 2 root root 4096 Jul 18 12:19 test1
Use Previous Command's Arguments
Running a command with the same arguments used in the previous command, use '!*' to repeat all arguments or '!:2' to use the second argument. '!$' uses the last argument. Let's see a few examples.
Code:
[root@pradeep ~]# mkdir -p /tmp/pradeep/test/shell [root@pradeep ~]# cd !$ cd /tmp/pradeep/test/shell [root@pradeep shell]# mkdir -p /tmp/pradeep/test2 /tmp/pradeep/test3 [root@pradeep shell]# chmod -R 777 !:2 !:3 chmod -R 777 /tmp/pradeep/test2 /tmp/pradeep/test3 [root@pradeep shell]# touch a.txt b.txt [root@pradeep shell]# ls !* ls a.txt b.txt a.txt b.txt [root@pradeep shell]# ls -l !* ls -l a.txt b.txt -rw-r--r-- 1 root root 0 Aug 10 13:54 a.txt -rw-r--r-- 1 root root 0 Aug 10 13:54 b.txt [root@pradeep shell]#
Ctrl+U - Cuts everything to the left
Ctrl+W - Cuts the word to the left
Ctrl+Y - Pastes what's in the buffer
Ctrl+A - Go to beginning of line
Ctrl+E - Go to end of line
Ctrl+R - Search command history
Changing File Extensions
Code:
rename 's/.html$/.html.bak/' *.html
Run a second command only if the first one is successfull
Code:
cd /tmp/pradeep/test/shell && tar xjvf /home/pradeep/songs.tar.bz
