In this article, we have listed out the commands that you could use in a Linux for increasing your productivity.
Find and kill and process
Let’s say you want to find a process id and kill it. You can do this using the following command.
# ps -aef | grep <service name> | grep -v grep | awk ‘{print $2}’ | xargs kill -9
Find maximum space using files
Sometimes in production our filesystem get full or about to. This is due to some unwanted file get full frequently. To find those files
# find / -xdev -size +94371840c -exec du -h {} \;
or
# find / -xdev -size +50000 -exec ls -s {} \; |sort -n
List out all process and Listening ports
Use the following command to list all the listing ports.
# netstat –nulpn
Delete the last Word and Line
When you are typing,
- If you want to delete the last word, use “Ctrl + W”
- If you want to delete the whole line, use “Ctrl + U”
- If you want to enter next line, use “Ctrl + C”
Search Previously Executed Command
You can search for a previously executed command using the reverse search functionality.Use “Ctrl + R” button and type the keyword to search. It will return the matching command executed before.
Process related
- Use pgrep to get the process id of a service.
# pgrep <service name>
And you can use xargs to kill all the related processes.
# pgrep <service name> | xargs kill -9
- User nohup and & to send a process to the background and run forever.
# nohup <some Service/process script> &
Output as file Input
You can use the output of a command as a file to be the input of another command using “<” symbol.
For example, if you want to compare the /etc/hosts of a remote host with your current host, you can do the following.
# diff /etc/hosts <(ssh user@<IP> -i ~/.ssh/key-file cat /etc/hosts)
Suppress the standard output
If you want to suppress the standard output, you can redirect the stdout to /dev/null
For example,
# ls -l > /dev/null
File Permissions in Octal form
To view the file permissions in octal form, you can use the following syntax.
# stat -c ‘%A %a %n’ <file name>
disk/CPU/network status
To know disk/CPU/network status you could use the following command line utilities.
# iostat
# netstat
# top
# vmstat
Other useful Tips
- Use Ctrl + Z to suspend a process
- Use grep for filtering outputs
- Use !! to execute the last command
- Use dmesgcommand to identify hardware or driver problems
- Use the mtrcommand to troubleshoot network issues.
For example,
mtr 8.8.8.8
- To empty a file use >followed by the filename. For example >example.txt
- Use pstree command to view the process tree of your system.