Shell script error: [: 0: unary operator expected

Question

Using this if statment in bash :

if [ "$TOTAL_LOAD" >= "2" ];then

RESULT=$STATE_WARNING

msg_text="The system load on $HOST is greater than 200% please investigate {$TOTAL_LOAD}"

fi

Getting the error:

 line 28: [: 0: unary operator expected

Not seeing the error in my ways. Anyone able to help?

Answer 1

Bash uses different operators for string vs arithmetic comparison. You want -ge instead of >= :

if [ "$TOTAL_LOAD" -ge "2" ];then

Answer 2

If I run this by hand I see the error:

pokyo. if [ "0" >= "2" ]; then echo hi; fi
bash: [: 0: unary operator expected

The problem is that ">=" is not a valid operator for test . Instead you must write -ge :

pokyo. if [ "0" -ge "2" ]; then echo hi; fi