source - is a built-in shell command that reads and executes the file content in the current shell.

syntax $ source [filename] [arguments]

To pass commands and arguments $ cat example.txt free -h pwd date time uptime $ source example.txt

To read variables from a file $ cat example.sh #!/bin/bash VAR1="a" VAR2="b" VAR3="c"

create bash script $ cat sample.sh #!/bin/bash source example.sh echo "VAR1 is $VAR1" echo "VAR2 is $VAR2" echo "VAR3 is $VAR3"

$ source sample.sh

To refresh the current shell environment $ alias ll = 'ls -l' $ alias c = 'clear' $ c $ ll This command only works in the current shell session To make it permanent $ sudo nano ~/.bashrc alias ll = 'ls -l' alias c = 'clear' :x Refresh the current shell environment and make it permanent for the user $ source ~/.bashrc

To make it system wide change $ sudo vim /etc/profile alias ll = 'ls -l' alias c = 'clear' :x

# source /etc/profile

regards, T.Dhanasekar