Command Combination
CHEATSHEET
A; B Run A and then B, regardless of success of A
A && B Run B if A succeeded
A || B Run B if A failed
A & Run A in background.
Running command in single line.
1st Choice
ls ; pwd ; whoami
2nd Choice ||| The Logical AND Operator (&&)
If you want the second command to only run if the first command is successful, separate the commands with the logical AND operator, which is two ampersands ( && ).
mkdir DirData && cd DirData
3rd Choice ||| The Logical OR Operator (||)
The logical OR operator, or two vertical bars ( || ). For example, we want to check to see if the MyFolder directory exists ( [ -d ~/Documents ] ) and create it if it doesn’t ( mkdir ~/RexTmpora ).
[rx@localhost ~]$ [ -d ~/Documents ] || mkdir ~/RexTmpora
[rx@localhost ~]$ cd RexTmp/
Combining the command
[ -f ~/sample.txt ] && echo “File exists.” || touch ~/sample.txt
sudo apt-get update && sudo apt-get install pyrenamer
&& can be equivalently paraphrased IN a script.
if sudo apt-get update ; then
sudo apt-get install pyrenamer
fi