# this is to show you how to execute a series of commands in one strike.
$ clear; cd /; ls -l; echo "You are in $PWD"; echo "Time to go back home"; cd ~;
# use semi colon between each command.
# There is also command lists, which is for a different logic
## double ampersand means ANDING, double pipe means ORING; when using &&, only when the first command exits 0 (successful), the later command will be proceeded; when using ||, if the first command exits none zero (not successful), the later command will be proceeded;
$ ls -l && you are in $PWD, you were in $OLDPWD
$ ls -z || you are in $PWD