Command line Options or Flag

By using an option, you can modify what your original command does. Most commands have plenty of options. You can apply them by:

  1. typing your original command (e.g. wc)

  2. then a space and a dash ( -)

  3. then the option name (e.g. w

General syntax:

command -option 

A few e.g.:

wc -w some_data.csv
On its own, wc counts the number of lines, words and characters in some_data.csv. But with the -w option, it only counts words. 

ls -l
ls lists all the content of your current working directory.
But with the -l option, it also displays additional information for the given files and directories (e.g. size, date of creation, owner, permissions)

tail -50 some_data.csv
tail prints the last 10 rows of the some_data.csv file.
But with the -50 option, it prints the last 50 rows instead.