man bash

ls

ps -ef
ps -ef | awk '(print $1)' | sort | uniq -c

vim hello.sh

hello.sh:
ls

./hello.sh

ls -l 

man chmod

chmod u+x hello.sh
chmod ugo+x hello.sh
chmod go-x hello.sh
chmod 764 hello.sh

ls -l hello.sh

./hello.sh