Backup , compressions, Automatic execution of commands

#du -sh dir name or file name ( to check size of file or directory )
# tar cvf filename .tar directory name (backup and compression done up to 40%-50%)
c- create
v - visual
f-file extension sport
# tar tf filename .tar ( to check the file )
#gzip -9 filename.tar ( high level compression and convert into file into .gz)

#tar zxvf filename.tar.gz ( decompress)

Automatic execution of commands
> first find path of command
#whereis command name
> then open crontab
#crontab -e
then add entry like this
*(for mintue) *(for hour) *( for date) *(for month ) *(for day of week 1-7)

forexample:-
44 19 12 7 7 /bin/reboot(path of commands)

save and exit

> then
# service crond restart