linux - How to code bash script to allow entire commands with spaces? -

so basically, i'm looking way make below bash script work without issue. each of commands works when tested individually, it's in actual script has problem. code below:

#!/bin/bash  answer="$(/usr/bin/grep "permitrootlogin yes" /etc/ssh/sshd_config)"    if [ $answer ];        (perl -pi -e \'s/\"permitrootlogin yes\"/\"permitrootlogin no\"/g\' /etc/ssh/sshd_config)  else     echo "root login not permitted, no values changed." fi 

here's happens when try run it:

test.sh:  line 9: [: permitrootlogin: unary operator expected root login not permitted, no values changed. 

so basically, rather doing find/replace want on file via perl command, it's trying interpret separate instruction.

all attempting @ /etc/ssh/sshd_config file , change relevant entry yes no if "answer" found yes.

i'm looking way make work. i've looked @ lot of bash examples on site none of them seem cover specific case.

also, reason i'm using perl sed works oddly on solaris 11, or isn't installed on extremely old versions, , perl installed on every version 8 forward.

any ideas?

double quote variable in square brackets.

if [ "$answer" ] ; 

otherwise, it's expanded , word-split, [ doesn't know 2 words (it expects first 1 unary operator -f error's telling you).