UNIX for Advanced & Expert Users

I'm kinda new to unix programming so bear with me...

I'm running a script prompting a user for an existing user and group and want to be able to validate if they valid.

Is there any code available?

Any help or push in the right direction would help.

Thank you,

here are some pointers ...

1. get input from user and assign that to a variable

2. grep out the variable from /etc/passwd (or whatever file your OS uses) and assign the GID to another variable

3. grep out the GID from /etc/group (or whatever file your OS uses)

... if you can grep out the username and the GID from the appropriate files, then your inout is validated ...

### check man pages for grep, awk, cut and ksh ... good luck!

If you don't want to parse the system user files yourself
you could as well use a system command like id.
e.g.

Code:

echo "enter user:"
read user
if [[ -n $user ]] && id $user >/dev/null 2>&1; then
    # user is known
    # do whatever you like
fi