Bash - looping or capturing a multiple line co ...

Sunday, April 15. 2012

Bash - looping or capturing a multiple line command output

I tried to loop a command which returns a multi-line result in a bash script. The problem was that the quoted command returned ONE line instead of each line separately. So I ended with one line consisted of multi-line result while I was expecting that the quotes would preserve the spacing. Without quotes I got each "word" in a new line while I was expecting everything in one line (without quotes should replace multiple blanks, tabs and newlines with a single space). Here is the "faulty" script:

#for line in `ls -l`
#for line in $(ls -l)
for line in "$(ls -l)" 
do
    echo $line"XXX"    
done

Not quite sure if this is due to OS X (or BSD) environment but I got around it by piping the command to the while loop:

(ls -l) | while read line
do
     echo $line"xxx"
done

or

while read line; do
    echo $line"xxx"
done < <(ls -l)