Assign the result of a multiline command to a variable


 
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# 1  
Old 11-20-2013
Assign the result of a multiline command to a variable

Hi,
I have the following command that lists all the .o files from all the directories except of vwin (which I don't want it)
Code:
for i in `ls -d */*.o|awk '$0 !~ "vwin"'`; do echo $i; done

The result is something like that
Code:
dir1/file1.o
dir1/file2.o
dir2/file3.o
etc.

So, I want to create a variable which will have the following value:
Code:
var1="dir1/file1.o dir1/file2.o dir2/file3.o"

I tried first to do that
Code:
echo `for i in `ls -d */*.o|awk '$0 !~ "vwin"'`; do echo $i; done`

in order to have the multiple lines to one. Unfortunately it doesn't work because of the ";" (I guess).

Can someone help?
Thanks

Last edited by Scrutinizer; 11-21-2013 at 02:27 AM..
# 2  
Old 11-20-2013
That command is extremely redundant. You do not need to cram awk's output into a for-loop to make it print. Leave it out of the loop completely.

ls -d */*.o|awk '$0 !~ "vwin"

It didn't work because you can't nest backticks in that way, it will take the second ` to be the end of the first, not an inner set. For this reason modern shells use $( ) instead of backticks since they nest without trouble. You don't need to nest anything, though.

So your command, with the useless loop removed, boils down to:

Code:
VAR=$(ls -d */*.o|awk '!/vwin/')


Last edited by Corona688; 11-20-2013 at 05:38 PM..
# 3  
Old 11-20-2013
It is more versatile to store the multi-line in VAR.
So you have the option of echo "$VAR"
or on-the-fly folding with (set -f; echo $VAR) or echo "$VAR" | paste -sd " " -
# 4  
Old 11-20-2013
OK then:

Code:
VAR="$(ls -d */*.o|awk '!/vwin/')"

# 5  
Old 11-21-2013
Quote:
Originally Posted by Corona688
OK then:

Code:
VAR="$(ls -d */*.o|awk '!/vwin/')"

The quotes are not useful. Your previous post was already multiline.

Last edited by MadeInGermany; 11-21-2013 at 02:18 AM..
# 6  
Old 11-21-2013
putting a list of files in a string variable assumes the files won't have whitespace in them and this can break things. ideally you'd process them more carefully. if you're using bash, there are arrays and extglob.

Code:
shopt -s extglob
files=( */!(*vwin*).o )

for f in "${files[@]}"; do
   ...
done

# 7  
Old 11-21-2013
Another way

Code:
var=`ls -d */*.o | grep -v vwin`

Now var has the value of all the *.o files

Last edited by Scott; 11-21-2013 at 08:45 AM.. Reason: Added code tags [6th time in 7 posts]
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