CODE EXAMPLE FOR SHELL

linux change password chpasswd

# Chpasswd command is very simple to use 
[ root@myhost ~ ] # echo "tom:1234" | chpasswd
 
# Using the passwd command, you can also change the password in a batch like mode
[ root@myhost ~ ] # echo "1234" | passwd --stdin "tom" 
Changing password for user tom.
 passwd: All authentication tokens Updated successfully.