replace 'sha256sum -c' with openssl / cmp in bash

sha256sumc.sh

#!/bin/bash
sha256sumc () 
{ 
    local err file hash out rc=0;
    while IFS=' ' read -r hash file; do
        file="${file#[*]}";
        out="$(openssl dgst -sha256 -r "$file" 2>/dev/null)" && cmp -s <(echo "$out") <(printf -- '%s *%s\n' "$hash" "$file") && printf -- '%s: OK\n' "$file" || { 
            printf -- '%s: FAILED' "$file";
            err="$(openssl dgst -sha256 -r "$file" 2>&1 >/dev/null)";
            if [[ "$err" =~ ': No such file or directory'$'\n' ]]; then
                printf -- ' %s' 'open or read';
            fi;
            printf -- '\n';
            rc=1
        };
    done <"${1:-/dev/stdin}" || rc=$?;
    return $rc
}