Grep multiple bash parameters

Question

I'm writing a bash script which shall search in multiple files.

The problem I'm encountering is that I can't egrep an undetermined number of variables passed as parameters to the bash script

I want it to do the following:

Given a random number of parameters. i.e:

./searchline.sh A B C

Do a grep on the first one, and egrep the result with the rest:

grep "A" * | egrep B | egrep C

What I've tried to do is to build a string with the egreps:

for j in "${@:2}";
do
ADDITIONALSEARCH="$ADDITIONALSEARCH | egrep $j";
done

grep "$1" * "$ADDITIONALSEARCH"

But somehow that won't work, it seems like bash is not treating the "egrep" string as an egrep.

Do you guys have any advice?

By the way, as a side note, I'm not able to create any auxiliary file so grep -f is out of the line I guess. Also note, that the number of parameters passed to the bash script is variable, so I can't do egrep "$2" | egrep "$3".

Thanks in advance.

Fernando

Answer 1

A safe eval can be a good solution:

#!/bin/bash

if [[ $# -gt 0 ]]; then
    temp=(egrep -e "\"\$1\"" '*')

    for (( i = 2; i <= $#; ++i )); do
        temp+=('|' egrep -e "\"\${$i}\"")
    done

    eval "${temp[@]}"
fi

To run it:

bash script.sh A B C