Extension Attribute script logic help

[daworley]

I have a custom script that I cobbled together to determine if the PolicyBanner file is in place. This is then scoped against to install the PolicyBanner via a package.
http://support.apple.com/kb/HT4788

The original version of this script works just fine. As soon as I added the <result> brackets and input it into the Extension Attribute (data type=string, populated by script) it doesn't seem to work.

Testing the logic by removing/renaming the file does not update in the Inventory report.
Anybody care to tell me what I did wrong? :)

#!/bin/bash
ls -alh /Library/Security/ | grep PolicyBanner
if [ "$?" = 0 ] then echo <result>Yes_PolicyBanner</result>
else echo <result>No_PolicyBanner</result>
fi

[stevewood · Accepted solution]

Looks like you are missing the quotes in your <result> statements:

echo "<result>Yes_PolicyBanner</result>"
echo "<result>No_PolicyBanner</result>"

Steve

[daworley · Accepted solution]

Steve,

Thanks for the help.

Here is the updated version. This does the trick.

#!/bin/bash
ls -alh /Library/Security/ | grep PolicyBanner
if [ "$?" = 0 ] then echo "<result>Yes_PolicyBanner</result>"
else echo "<result>No_PolicyBanner</result>"
fi

[stevewood · Accepted solution]

Looks like you are missing the quotes in your <result> statements:

echo "<result>Yes_PolicyBanner</result>"
echo "<result>No_PolicyBanner</result>"

Steve

[daworley · Accepted solution]

Steve,

Thanks for the help.

Here is the updated version. This does the trick.

#!/bin/bash
ls -alh /Library/Security/ | grep PolicyBanner
if [ "$?" = 0 ] then echo "<result>Yes_PolicyBanner</result>"
else echo "<result>No_PolicyBanner</result>"
fi

[rmanly · Accepted solution]

Don't make a habit of parsing ls. Also, there are much better ways to test if something exists etc.

This is what you want:

#!/bin/bash

if [[ -e /Library/Security/PolicyBanner.txt ]]; then
    echo "<result>Yes_PolicyBanner</result>"
else
    echo "<result>No_PolicyBanner</result>"
fi

And if you truly do not know if it will be a .txt, .rtf, or an .rtfd and you don't care then this will tell you if anything called PolicyBanner exists

#!/bin/bash

shopt -s nullglob
bannerfiles=(/Library/Security/PolicyBanner.*)

if [[ ${#bannerfiles[@]} -gt 0 ]]; then
    echo "<result>Yes_PolicyBanner</result>"
else
    echo "<result>No_PolicyBanner</result>"
fi

Why you shouldn't parse the output of ls(1)
http://mywiki.wooledge.org/ParsingLs

Tests and Conditionals
http://mywiki.wooledge.org/BashGuide/TestsAndConditionals

Also, for future cases where you really need it grep -q will do what you were kinda trying to do by checking the exit status.

Start Here.
http://mywiki.wooledge.org/BashGuide

The LDP "Bash Guide for Beginners" and ABS aren't the greatest.

[tlarkin]

Yes, bash has a lot of built in functions to check if files exist, if something is a directory, if it is a file and so forth. These require less code and run with in the shell itself, so they should technically also be more efficient.

[rmanly]

YEP!

mine run in .006 and .007 seconds respectively. The one with the "| grep" takes .012!

lol. :D

In all seriousness though spawning subshells, using pipes and external programs will add up in really big scripts. They also tend to be more fragile.

[tlarkin]

Haha, but hey you'll never get those 0.05 seconds back!

[CasperSally]

This thread helped me figure out building an extension attribute I needed in a rush, thanks for posting.