[SOLVED] convert for each loop from csh to bash

budgie26 · 06-22-2014, 08:31 PM

I have a csh script I'm trying to convert to bash but I'm having problems with getting a for each loop to work properly. The loop is within an if statement:

Code:

if [ -e $file_list ]; then
   while read -r i; do
       mkdir $dir/file_$i
   done < $file_list
else
   :
fi

If the $frame_list file exists, then a directory needs to be created for each line in the file. The file has the directory name on each line:

2654
2655
2656

I've tried changing the NFS format to newline, but can't get the for each loop to move beyond the first line (ie. 2654).

This is probably a simple fix, but I can't work it out. Any advice would be appreciated!

evo2 · 06-22-2014, 08:45 PM

Hi,

it looks to me like your script should work. Can you confirm that the input file is a normal text file? Also, is the directory really being created? It would be best to try to reduce this to the simplest possible script that still has the problem. Eg, get rid of the "if" statment and variables. Eg something like

Code:

#!/bin/bash
while read dir ;do 
  echo "dir is $dir"
done < foo.txt

Evo2.

budgie26 · 06-22-2014, 09:01 PM

I've recreated the input file in emacs, so it should be a normal text file (I just typed in the dir names and pressed enter after each one). I've also tested the loop by its self in a test script and I still get the same problem: only the first dir gets created.

evo2 · 06-22-2014, 09:11 PM

Hi,

you need to debug your script... try using "set -x" at the top of the script.

Evo2.

pan64 · 06-23-2014, 12:29 AM

The "usual" reason is that something eats up the stdin inside the loop. Actually you didn't show us the real script, therefore there can be something next to the mkdir command. The solution is something like this:

Code:

while read dir ;do 
  echo "" | ( your commands )
done < foo.txt

but in any case you can insert set -xv at the beginning of the script to see what's happening.

budgie26 · 06-23-2014, 01:29 AM

Found what the problem is. The last line of the input file needs have a 'return' after the last line. Something so simple can be so frustrating!! Thanks for all your help!!