Question

I’ve been using the following call to sed to remove lines files.

sed "/% Program:/,/mode: SPIKE/d" file.tt > file.tt.nh

I tried writing a bash script to allow me to run the script on many files at once. However sed fails.

sed "/% Program:/,/mode: SPIKE/d" file.tt > file.tt.nh
sed: -e expression #1, char 1: unknown command: `"'

This is the script I’ve written that isn’t working

#!/bin/bash
SEDARG='"/% Program:/,/mode: SPIKE/d"';
for F in *.tt
do
  OUT=$F'.nh';
  echo 'sed '$SEDARG' '$F' > '$OUT;
  sed $SEDARG $F > $OUT
done

What perplexes me is if I copy the echo’d string and paste it in the command line it works fine.

Does anyone know why this script is failing but the command line call works?

Answer 1

Quoting is tricky. Basically, move the double quotes from where you assign to $SEDARG to where you use $SEDARG.

SEDARG='/% Program:/,/mode: SPIKE/d'
for F in *.tt
do
  OUT="$F.nh"
  echo "sed $SEDARG $F > $OUT"
  sed "$SEDARG" "$F" > "$OUT"
done