[SOLVED] a simple bash construct to generate a list

David1357 · 02-21-2011, 05:13 PM

Quote:

Originally Posted by nass

I would expect that the above construct would fill in the variable FOLDER_LIST with a list of folders from the current directory.

Will this work?

Code:

#!/bin/bash
pushd /usr/share/doc

FOLDER_LIST=( $(ls -dAl * | grep -v "^l" | awk '{ print $8 }') )
for (( INDEX = 0 ; INDEX < ${#FOLDER_LIST[@]} ; INDEX++ )) ; do
    echo "FOLDER_LIST[$INDEX] = ${FOLDER_LIST[$INDEX]}"
done

popd

The idea for the array code came directly from the Linux Documentation Project pages for bash.

nass · 02-21-2011, 05:20 PM

tried GazL but...

Quote:

./users2: line 15: syntax error near unexpected token `<'
./users2: line 15: `done < < ( ls -d $PWD | grep -v "lost+found" )'
[/share/MD0_DATA] #

did you intentionally leave a gap between the 2 redirects? < < ??

and also if you run the script like that, on the 1st pass of the while loop, what will be the value of the $directory?
(should i safely assume that the statement next to the 'done' while loop will be run in order to give a value to the $directory?)

GazL · 02-21-2011, 05:29 PM

Quote:

Originally Posted by nass

tried GazL but...

did you intentionally leave a gap between the 2 redirects? < < ??

and also if you run the script like that, on the 1st pass of the while loop, what will be the value of the $directory?
(should i safely assume that the statement next to the 'done' while loop will be run in order to give a value to the $directory?)

Yes the space is intentional. < <( command ) is a bash specific way of doing a command | while read ....
Bash starts pipelines in subshells where as traditional shells don't and that can cause problems with referencing variables sometimes.

It's possible that your shell isn't bash but is sh instead in which case my examples wont work as sh doesn't support the < <( command ) syntax.
But back at the very beginning you said it was a bash script, so that's what I wrote.

nass · 02-21-2011, 07:04 PM

indeed GazL, the busybox is running sh rather than bash - i only now realise too.

In the end I set aside the idea of lists. I was looking for lists thinking that they are more dynamic. But then again in bash arrays are dynamic too. so no reason to look for lists (too much C programming I guess).

here is what I have, using arrays in the end (as David1357 suggested)...

Code:

#!/bin/sh

USERS_DIR="/share/MD0_DATA/"
cd $USERS_DIR

FOLDER_LIST=( $( ls -d1 * | grep -v "\*$" ) )
#echo "FOLDER_LIST items = ${#FOLDER_LIST[@]}"
#echo "FOLDER LIST wc = " `ls -dA1 * | wc -l`

USERS_LIST=( $( cat /etc/passwd | cut -d":" -f1 ) )
#echo "USERS_LIST items = ${#USERS_LIST[@]}"


for (( INDEX = 0 ; INDEX < ${#FOLDER_LIST[@]} ; INDEX++ )) ; do
    echo "FOLDER_LIST[$INDEX]=${FOLDER_LIST[$INDEX]}"
    for (( i = 0 ; i < ${#USERS_LIST[@]} ; i++ )) ; do
        echo "USERS_LIST[$i]=${USERS_LIST[$i]}"
        if [[ "${FOLDER_LIST[$INDEX]}" == "${USERS_LIST[$i]}" ]] ; then
            echo "found a match ${FOLDER_LIST[$INDEX]} is matched to ${USERS_LIST[$i]}"
        fi
    done
done

the two lists are working 'fine'. as in the array cells get filed up almost as expected (exception: in FOLDER_LIST the 'network recycle bin' folder is perceived as 3 different elements but its OK for now.)

thank you all for your help
Goodnight