macos - Bash：引数をifステートメントと比較する方法は？

Question

次のコードを使用して、OSXでbashの引数を比較しようとしています...

 #!/bin/bash

if ["$1" == "1"]
then
        echo $1
else
        echo "no"
fi

しかし、私は次のエラーを受け取り続けます

$bash script.sh 1

script.sh: line 3: [1: command not found
no

「1」を評価しようとするのを防ぐにはどうすればよいですか？

Answer 1

[ is a test command, so you need a space between [ and "$1", as well as a space between "1" and the closing ]

Edit

Just to clarify, the space is needed because [ is a different syntax of the test bash command, so the following is another way of writing the script:

#!/bin/bash

if test "$1" == "1"
then
        echo $1
else
        echo "no"
fi

Which can be further simplified to

#!/bin/bash
[ "$1" == "1" ] && echo "$1" || echo "no"