extract fields of a string separated by |

Question

In the below shell script I want to extract the fields of a string delimited by | character. But unfortunately I'm facing issue if there exists pipe command | in the string, because of which I'm not able to extract the required fields

#!/bin/bash

_a=""
b=""
_c=""
_d=""

test_def1="abc|pidof abc|0|0"
if [[ "$test_def1" == *"|"*"|"*"|"* ]]; then
        echo "valid"
        IFS='|' read -r _a b _c _d <<< "${test_def1}"
        readarray -t _process_ids < <(ssh -o StrictHostKeyChecking=no -l root 192.168.1.50 "$b")
else
        echo "invalid"
fi

test_def2="abc|ps -a | awk "/abc/ { print \$1 }"|0|0"
if [[ "$test_def2" == *"|"*"|"*"|"* ]]; then
        echo "valid"
        IFS='|' read -r _a b _c _d <<< "${test_def2}"
        # expecting b to contain ps -a | awk "/abc/ { print \$1 }"
        readarray -t _process_ids < <(ssh -o StrictHostKeyChecking=no -l root 192.168.1.50 "$b")
else
        echo "invalid"
fi

Current output

valid
pidof abc
main.bash: line 18: {: command not found
invalid

Expected output

valid
pidof abc
valid
ps -a | awk "/abc/ { print \$1 }"

Answer 1

It's not clear why you're trying to do what you show, nor whether or not there are any other use cases to be considered, but this would produce the output I think you want from the relevant code sections given the input you provided:

$ re='^[^|]*[|](.*)([|][^|]*){2}$'

$ test_def1='abc|pidof abc|0|0'
$ if [[ "$test_def1" =~ $re ]]; then echo "${BASH_REMATCH[1]}"; fi
pidof abc

$ test_def2='abc|ps -a | awk "/abc/ { print \$1 }"|0|0'
$ if [[ "$test_def2" =~ $re ]]; then echo "${BASH_REMATCH[1]}"; fi
ps -a | awk "/abc/ { print \$1 }"