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