Assigning variable from command outputs to shell Post: 302329445

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Top Forums Shell Programming and Scripting Assigning variable from command outputs to shell Post 302329445 by staze on Saturday 27th of June 2009 10:10:38 PM

06-27-2009

Registered User

Assigning variable from command outputs to shell

First, this is bash (3.2.17), on a Mac, 10.5.7.

What I'm trying to do is look at a list of users, and check to see if each exists. If they do, do some more stuff, if they don't, drop them into an error file.

So, my user list is:
foo - exists
bar - does not exist
blah - does not exist

K, so, here's the script:

Code:

#!/bin/bash

#This script will take two arguments, the group name, and the user list. 
#It is recommended that the group be cleared before running this script since
#it will not remove people from the group.

if [ "$#" != "2" ]; then
echo -e "Usage of the groupadd script: $0 groupname userlist\n"
exit 1
else

group="$1"
userlist="$2"

echo "Adding users in $userlist to group $group"

read -p 'Enter username with directory write : ' admin
read -p 'Enter password for user : ' -s password

echo "test user: $admin, test pass: $password"
echo "group: $group, userlist: $userlist"

for user in `cat $userlist`; do
	check=$(id -u $user | grep "no such user")
	if [ $check != NULL ]; then
		echo "blah"
		#echo "User $user does not exist!" 
	fi
done
fi

I am obviously going to do more. The issue is, the output from id ends up outputting to the shell, rather than "blah". So, in the case of bar and blah, I get:
"id: bar: no such user
id: blah: no such user"
output to the shell. Where, I'd THINK that I'd get the output:
"blah
blah"

Anyone got any idea what's wrong?

Thanks!

staze

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checkbashisms

CHECKBASHISMS(1)					      General Commands Manual						  CHECKBASHISMS(1)

NAME

       checkbashisms - check for bashisms in /bin/sh scripts

SYNOPSIS

       checkbashisms script ...
       checkbashisms --help|--version

DESCRIPTION

       checkbashisms, based on one of the checks from the lintian system, performs basic checks on /bin/sh shell scripts for the possible presence
       of bashisms.  It takes the names of the shell scripts on the command line, and outputs warnings if possible bashisms are detected.

       Note that the definition of a bashism in this context roughly equates to "a shell feature that is not required to be supported  by  POSIX";
       this means that some issues flagged may be permitted under optional sections of POSIX, such as XSI or User Portability.

       In  cases  where  POSIX	and  Debian  Policy  disagree, checkbashisms by default allows extensions permitted by Policy but may also provide
       options for stricter checking.

OPTIONS

       --help, -h
	      Show a summary of options.

       --newline, -n
	      Check for "echo -n" usage (non POSIX but required by Debian Policy 10.4.)

       --posix, -p
	      Check for issues which are non POSIX but required to be supported by Debian Policy 10.4 (implies -n).

       --force, -f
	      Force each script to be checked, even if it would normally not be (for instance, it has a bash or non POSIX shell shebang or appears
	      to be a shell wrapper).

       --extra, -x
	      Highlight lines which, whilst they do not contain bashisms, may be useful in determining whether a particular issue is a false posi-
	      tive which may be ignored.  For example, the use of "$BASH_ENV" may be preceded by checking whether "$BASH" is set.

       --version, -v
	      Show version and copyright information.

EXIT VALUES

       The exit value will be 0 if no possible bashisms or other problems were detected.  Otherwise it will be the sum of the following error val-
       ues:

       1      A possible bashism was detected.

       2      A file was skipped for some reason, for example, because it was unreadable or not found.	The warning message will give details.

SEE ALSO

       lintian(1).

AUTHOR

       checkbashisms  was originally written as a shell script by Yann Dirson <dirson@debian.org> and rewritten in Perl with many more features by
       Julian Gilbey <jdg@debian.org>.

DEBIAN
								 Debian Utilities						  CHECKBASHISMS(1)

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