Linux Commands: Essentials

Being equipped with the general Linux commands in your toolkit is a really good thing as a software engineer. It is a sort of gray area in terms of what you are supposed to know and why can't someone google such stuff? Having a good understanding of what commands exist can give you a starting point from where to look. So let us dive straight in. I will keep updating this list as I find commands.

• ls: The ls command can be used to list files.

  • ls -a lists all the hidden files as well

  • ls -R recursively lists down all the files in the subdirectories.

  • -t option will sort the entries by modification date

• cat: It is used to list the contents of the file.

  • -n : Lists the contents of the file along with the line number.

  • cat fileOne fileTwo : Copies contents from file one to file two

• tail: It is used to print the last 10 lines of the file.

  • It can be used to continuously watch changes to a file

• chmod: It is used to change file permissions in linux

  • The digits 7, 5, and 4 each individually represent the permissions for the user, group, and others, in that order. Each digit is a combination of the numbers 4, 2, 1, and 0

• grep : It is used to search regex in the file structure

• ps: It is used to list processes.

  • ps -A: It is used to list all the running processes.

  • ps -p p_id: It is used to list the process with a given pid

  • aux: It displays a list of information you might need on how the different information reported by various lists of processes.

• top: It is used to monitor the vitals of the system and can give you an overview of how your system is performing.

• wget: It is used to download files from the internet.