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I seem to be having trouble with a piece of code I'm writing (at least I think anyways). It's a script that parses a text file called test3_data.txt with a bunch of user ID's in them, and puts those user Id's into a variable called "USER_ID". I then test to see if they have a home directory with whatever text is in the USER_ID variable. If so, it deletes the user from the system, along with their files, home directory, etc. The script works fine, but when it's done running, the man pages for the userdel command show up. Is there anyway to stop that from happening? Is their something wrong with my code? Thanks! and here is my code.

!/bin/sh

while read IN_RECORD
do


#Variable that reads user id

USER_ID=`echo $IN_RECORD |cut -d'|' -f1`

#Remove added users from data file.

test -d /home/{$USER_ID}

if [ "$?" = "1" ];
then
userdel -r $USER_ID
fi

done < test3_data.txt
mcgovernmatt
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1 Answers1

5

A number of things are wrong with your script:

  • The shebang line should read #!/bin/sh (missing #), or #!/usr/bin/env sh

  • The variable reference {$USER_ID} is not what you intended - ${USER_ID} is the correct form (typically, just $USER_ID is enough).

  • You're incorrectly testing for success: it is exit code 0, not 1 that indicates success. Also, in a bash script you should use [[ instead of the deprecated [ for tests. (*)

One possible explanation for the command-line help (not the man page) showing is that $USER_ID is empty - the resulting invalid syntax then causes userdel utility to show its command-line help.

Finally, there are ways of streamlining your script:

  • A statement-ending ; is only needed if you place more statements on the same line.

  • Your test could be combined into a single statement: if [ -d "/home/$USER_ID" ]; then

(*): As @thom points out, [ and test still have their place, if your script must remain POSIX-compliant. By contrast, in a bash-specific script, [[ is preferable, because it is more convenient to use and has more features than [ - see http://mywiki.wooledge.org/BashFAQ/031.
Note that the OP's shebang line specified sh - which may or may not result in processing by bash, depending on the platform.

mklement0
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  • Thank you. I actually did have the # in the #!/bin/sh, but for some reason it didn't copy over onto here. Thank you for correcting me on the variable reference part. Although what I don't understand is how can the variable be empty? The script is running correctly, and removing the users/directories successfully (based on what is in that variable). – mcgovernmatt Nov 07 '13 at 03:27
  • Strike that...I reviewed my code once more and had forgotten to change something. It's now working perfectly..Thanks again! – mcgovernmatt Nov 07 '13 at 03:43
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    About the `[[`. I get a bit itchy lately about the word "deprecated". Good advice to read this: http://stackoverflow.com/questions/669452/is-preferable-over-in-bash-scripts which does give some food for thought. Then decide your coding style. – thom Nov 12 '13 at 01:07