1. ^foo^bar
This Ubuntu command helps to modify the last run command. This avoids the retyping of the whole command again and is helpful when typo’s occurs in a long command. The syntax of the command is ^typo_code^actual_code
Example:
pint localhost -c 3
greetz@ubuntu:~$ pint localhost -c 3 No command 'pint' found, did you mean: Command 'print' from package 'mime-support' (main) Command 'pinot' from package 'pinot' (universe) Command 'pinq' from package 'qmail' (universe) Command 'tint' from package 'tint' (universe) Command 'pinto' from package 'pinto' (universe) Command 'ping' from package 'iputils-ping' (main) Command 'ping' from package 'inetutils-ping' (universe) Command 'pinta' from package 'pinta' (universe) pint: command not found
^pint^ping
greetz@ubuntu:~$ ^pint^ping ping localhost -c 3 PING localhost (127.0.0.1) 56(84) bytes of data. 64 bytes from localhost (127.0.0.1): icmp_seq=1 ttl=64 time=0.023 ms 64 bytes from localhost (127.0.0.1): icmp_seq=2 ttl=64 time=0.019 ms 64 bytes from localhost (127.0.0.1): icmp_seq=3 ttl=64 time=0.022 ms --- localhost ping statistics --- 3 packets transmitted, 3 received, 0% packet loss, time 1998ms rtt min/avg/max/mdev = 0.019/0.021/0.023/0.004 ms
Note: Carelessly replacing the typo with system commands may be risky.
2. sudo !!
This command can be used in situation where you forgot to specify sudo for the root privileges before the command. sudo !! command recalls the last command and runs it with sudo permissions.
Example:
apt-get update
greetz@ubuntu:~$ apt-get update E: Could not open lock file /var/lib/apt/lists/lock - open (13: Permission denied) E: Unable to lock directory /var/lib/apt/lists/ E: Could not open lock file /var/lib/dpkg/lock - open (13: Permission denied) E: Unable to lock the administration directory (/var/lib/dpkg/), are you root?
sudo !!
greetz@ubuntu:~$ sudo !! sudo apt-get update [sudo] password for greetz: Get:1 http://security.ubuntu.com trusty-security InRelease [65.9 kB] Ign http://extras.ubuntu.com trusty InRelease ......
3. look
The look command can be a handy option to check for words from an English dictionary in case you have forgotten the spellings.
Example:
look geek
greetz@ubuntu:~$ look geek geek geek's geekier geekiest geeks geeky
4. tree
This command helps to list the current directory structure in a tree format. You have to first install the package ‘tree‘ (sudo apt-get install tree) in order to use this command.
Example:
tree
greetz@ubuntu:~$ tree . ├── Desktop ├── Documents │ ├── greetz to geeks.docx │ └── New User Manual.docx ├── Downloads ├── examples.desktop ├── Music ├── Pictures ├── Public ├── Templates └── Videos 8 directories, 3 files
5. ss
The ss command is a very useful and faster command which gives the socket statistics. It is a substitute for the netstat command.
Example:
ss
greetz@ubuntu:~$ ss Netid State Recv-Q Send-Q Local Address:Port Peer Address:Port u_str ESTAB 0 0 @/tmp/.X11-unix/X0 17472 * 17471 u_str ESTAB 0 0 * 16670 * 16671 u_str ESTAB 0 0 @/tmp/dbus-VQpvce49KE 17336 * 17335 ..........