csh Shell Script: Getting wc command output to variable to do math on it, how?

vxc69 · 05-04-2009, 04:05 PM

Hello guys,

A quick CSH question. I'm trying to run wc -l on a file. I want to get this line count on to a variable in my csh script. I'm not doing it right.

This is what i've tried to no avail:

Code:

1.) set numlinks = `cat` $file | wc -l
2.) numlinks = `cat` $file | wc -l

$file comes from a foreach loop. $file is ok because if I just run 'cat' $file | wc -l, it prints out the correct amount of lines.

Once I get this count into a variable I want to do some arithmetic on it. First time writing shell scripts by the way, so excuse my ignorance.

Thanks for any help,
vxc

colucix · 05-04-2009, 04:17 PM

Your commands don't work because you put backticks around the cat command only, whereas you have to embed the whole command line:

Code:

set numlinks = `cat $file | wc -l`

Then use expr to do arithmetic:

Code:

set numlinks = `expr $numlinks + 1`

Hope this helps.

Eycks · 05-04-2009, 04:17 PM

numlinks = <back quote>cat $file | wc -l<back quote>

My <back quote> key does not work. If this does not work try putting set in fron of numlinks

vxc69 · 05-04-2009, 04:22 PM

Quote:

Originally Posted by colucix

Your commands don't work because you put backticks around the cat command only, whereas you have to embed the whole command line:

Code:

set numlinks = `cat $file | wc -l`

Then use expr to do arithmetic:

Code:

set numlinks = `expr $numlinks + 1`

Hope this helps.

Oh! I thought that it would try to cat $file instead of what's in $file if i put that in back quotes too. Putting the entire thing in back quotes worked! Thanks. Well appreciated.

raconteur · 05-04-2009, 04:27 PM

Enclose the whole command in back quotes, and make sure your variable assignments don't have spaces around the equals signs.

For example:

Code:

foreach file (your_list)
  set numlinks=`cat $file | wc -l`
  echo "numlinks for $file is $numlinks"
end

hth

colucix · 05-04-2009, 04:31 PM

Quote:

Originally Posted by raconteur

and make sure your variable assignments don't have spaces around the equals signs.

Not strictly necessary in C-shells. That's true for Bourne-shells instead.