-bash: [: =: unary operator expected. when no parameter given [duplicate]

Question

I have my shell script, myscript.sh below

#!/bin/sh
if [ $1 = "-r" ]; then
    echo "I am here"
fi

If I run with . myscript.sh -r, it works well with message I am here.

But if I just run with . myscript.sh, it complaints

-bash: [: =: unary operator expected

What's missing in my script?

Elye · Accepted Answer · 2017-03-06 23:12:44Z

44

You would need to add quotes around $1.

if [ "$1" = "-r" ]; then
    echo "I am here"
fi

When $1 is empty you are getting if [ = "-r"] which is a syntax error.

Elye

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answered Mar 6, 2017 at 23:10

Bhakti Gandhi

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Comments

codeforester · Accepted Answer · 2017-03-06 23:08:35Z

11

You have missed the quotes:

if [ "$1" = "-r" ]; then

codeforester

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answered Mar 6, 2017 at 23:06

Slava Semushin

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