conditional binary operator expected in shell script

Question

I was trying a simple program to compare the string values stored on a log file and was getting an error as below,

#!/bin/bash  check_val1="successful" check_val2="completed" log="/compile.log"  if [[ grep $check_val1 $log -ne $check_val1 || grep $check_val2 $log -ne $check_val2 ]]; then         echo "No Error" else         echo "Error" fi   Error:  ./simple.sh: line 7: conditional binary operator expected ./simple.sh: line 7: syntax error near `$check_val1' ./simple.sh: line 7: `if [[ grep $check_val1 $log -ne $check_val1 || grep $check_val2 $log -ne $check_val2 ]];' 

Answer 1

Problem is in your if [[...]] expression where you are using 2 grep commands without using command substitution i.e. $(grep 'pattern' file).

However instead of:

if [[ grep $check_val1 $log -ne $check_val1 || grep $check_val2 $log -ne $check_val2 ]]; then 

You can use grep -q:

if grep -q -e "$check_val1" -e "$check_val2" "$log"; then 

As per man grep:

-q, --quiet, --silent          Quiet mode: suppress normal output.  grep will only search a file until a match           has been found, making searches potentially less expensive.