Question

I have quick question about text parsing, for example:

INPUT="a b c d e f g"

PATTERN="a e g"

INPUT variable should be modified so that PATTERN characters should be removed, so in this example:

OUTPUT="b c d f"

I’ve tried to use

tr -d $x

in a for loop counting by ‘PATTERN’ but I don’t know how to pass output for the next loop iteration.

edit:
How if a INPUT and PATTERN variables contain strings instead of single characters???

Answer 1

Pure Bash using parameter substitution:

INPUT="a b c d e f g"
PATTERN="a e g"

for p in $PATTERN; do
  INPUT=${INPUT/ $p/}
  INPUT=${INPUT/$p /}
done
echo  "'$INPUT'"

Result:

'b c d f'