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<H3 align="left"><img src="../../gx/dennis/qbubble.gif"
height="50" width="60" alt="(?) " border="0"
>script</H3>
<p><strong>From Paul Wilts
</strong></p>
<p align="right"><strong>Answered By Ben Okopnik
<br></strong></p>
<P><STRONG><IMG SRC="../../gx/dennis/qbub.gif" ALT="(?)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
Hello there, I am hoping you can help me out. I am writing a script. I have
a file that has two columns. one column with numbers and one column with
names. This file stores users disk-usage/user-name ie: 50000 paul. I would
like to run a script/command that would look into the file and if a user is
over a certain number , that number/numbers along with the user/users name
is copied from that file and put into a different file. I have tried almost
everything I know, which is limited, but have not had any success.
Thank you for your help
</STRONG></P>
<BLOCKQUOTE><IMG SRC="../../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [Ben]
Well, you don't say what it is that you tried, or what language the script
is in, but I'll take a flyer in a "bash" one-liner. If we have a file
called "quotas" that looks like this:
</BLOCKQUOTE>
<blockquote><pre>5 joe
7 jim
12 jack
10 jeff
20 jose
1 jerry
3 jenny
8 jamal
6 jude
</pre></blockquote>
<BLOCKQUOTE>
and we want only those users whose numbers exceed, say, 7, then we might
do something like this:
</BLOCKQUOTE>
<blockquote><code><font color="#000033"><br>while read a b; do [ $a -gt 7 ] && echo $a $b; done < quotas
</font></code></blockquote>
<BLOCKQUOTE>
What we've done here is read in each line and load the strings into two
variables, $a and $b. We then check to see if $a is greater than our
target number, and echo both of them if it is.
</BLOCKQUOTE>
<BLOCKQUOTE>
Note that the whitespace between the names and the numbers is ignored by
'read'; I only put it in to demonstrate how clever "bash" is about stuff
like that.
<IMG SRC="../../gx/dennis/smily.gif" ALT=":)"
height="24" width="20" align="middle">
</BLOCKQUOTE>
<BLOCKQUOTE>
You could also do it in Perl -
</BLOCKQUOTE>
<blockquote><code><font color="#000033"><br>perl -wane 'print if $F[0] > 7' quotas
</font></code></blockquote>
<BLOCKQUOTE>
- split each line into an array, print if the 1st member of the array
(arrays are indexed starting from 0) is greater than the target.
</BLOCKQUOTE>
<BLOCKQUOTE>
That should save lots of wear and tear on your fingers.
<IMG SRC="../../gx/dennis/smily.gif" ALT=":)"
height="24" width="20" align="middle">
</BLOCKQUOTE>
<P><STRONG><IMG SRC="../../gx/dennis/qbub.gif" ALT="(?)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
Thanks very much for your help. Yes I was using Bash. I tried using the test
and expr. What would you suggest for a good web site that would also be a
good reference for information on scripts. Once again thanks.
</STRONG></P>
<BLOCKQUOTE><IMG SRC="../../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [Ben]
Heh. I might have a suggestion.
</BLOCKQUOTE>
<BLOCKQUOTE>
A while ago, I wrote a 6-part series right here in Linux Gazette called
"Introduction to Shell Scripting". It's been translated into 7 languages,
and is used in at least two college courses. It was intended as a basic
text - don't expect to be introduced into The Deepest Mysteries - but I
believe that it's a very good start for anyone trying to learn shell
scripting, and should get you up to basic competence in short order.
</BLOCKQUOTE>
<BLOCKQUOTE>
Take a look at <EM>LG</EM> issues 52-55 and 57-58 or
<a href="<A HREF="http://www.linuxgazette.com/search.html"
>http://www.linuxgazette.com/search.html</A>">search for my last
name (Okopnik)</a>, since one of the articles got misnamed in the
e-mail shuffle.
</BLOCKQUOTE>
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