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 ]];'

Just curious -- Is there a way to use the [[ ... ]] but still make it work? — Meng Lu
– Meng Lu, Commented Aug 13, 2023 at 19:42

anubhava · Accepted Answer · 2014-08-04 12:36:13Z

40

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.

answered Aug 4, 2014 at 12:36

anubhava

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11 Comments

Angus Over a year ago

I executed like this on the shell grep -q -e "success" -e "leaving" compile.log > a cat a => was not listing any vlaue

anubhava Over a year ago

grep -q doesn't print anything on stdout. It just returns success/fail return value. If you remove -q then it will print values.

Angus Over a year ago

The log file contains the string "success" and "leaving".[root@a a~]# grep -e "success" -e "leaving" compile.log [root@aa~]# grep -e "success" -e "leaving" compile.log > a [root@aa~]# cat a [root@aa ~]# grep -e "suess" -e "leang" compile.log > a [root@aa ~]# cat a

anubhava Over a year ago

You can do: grep -iq -e "SUCCESS" -e "Leaving" "compile.log" for that case.

Angus Over a year ago

-e for the patern and -i to ignore the case. Thanks anubhava.

|

anothermh · Accepted Answer · 2023-04-04 08:03:43Z

21

[[ triggers the test command. Test doesn't support testing the exit status of a command just by typing the command

edited Apr 4, 2023 at 8:03

anothermh

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answered Mar 23, 2017 at 9:02

Robert Luo

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2 Comments

Carl G Over a year ago

How would you fix it?

pegasuspect Over a year ago

I came here to look for; briefly what brackets mean. Thanks.

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