Shell scripting trouble

[nebu]

I want to pass the output of

 grep -P "^[a-zA-Z0-9:]+\s+package" ctags_output.proc | awk '{print $1}'

to a script run.sh as its second argument ie

 ./run.sh pkg <argument>

what i am doing now is

 grep -P "^[a-zA-Z0-9:]+\s+package" ctags_output.proc | awk '{print $1}'| xargs ./run.sh pkg

but this is not working! what am i doing wrong??

[Brandon Williams]

If the output from the command is just supposed to provide arguments for run.sh, there's no need to use xargs. You can just use bash command substitution.

If you want the output to provide multiple white-space separated tokens:

./run.sh pkg $(grep -P "^[a-zA-Z0-9:]+\s+package" ctags_output.proc | awk '{print $1}')

If you want one single argument, then quote the command substitution expression:

./run.sh pkg "$(grep -P "^[a-zA-Z0-9:]+\s+package" ctags_output.proc | awk '{print $1}')"

If it still doesn't work, then run your script with the -x argument to get debugging output so you can figure out what's going wrong, as in:

bash -x ./run.sh pkg $(grep -P "^[a-zA-Z0-9:]+\s+package" ctags_output.proc | awk '{print $1}')

[nebu]

no.... i want every line of the output to got to a different ./run.sh so i was using the xargs!

[vijayanand_sodadasi]

If every line of output should go to separate instance of run.sh, then you can do it with a bit of shell scripting as follows:

for arg2 in $(grep -P "^[a-zA-Z0-9:]+\s+package" ctags_output.proc | awk '{print $1}')
do
   ./run.sh pkg $arg2
done

[Brandon Williams]

no.... i want every line of the output to got to a different ./run.sh so i was using the xargs!

Ah ... well, in that case, you should be using the '-L max-lines' option for xargs, or the for loop quoted above.

[bilkay]

Another way:

grep -P "^[a-zA-Z0-9:]+\s+package" ctags_output.proc | awk '{print $1} | while read x
do
     ./run.sh pkg $x
done

[David Andersson]

Option -l to xargs will run command once for each line in the input.
Option -n1 to xargs will run command once for each word in the input.
I think any would work in this case.