-bash: [: =: 预期的一元运算符。当没有给出参数时
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-bash: [: =: unary operator expected. when no parameter given
提问by Elye
I have my shell script, myscript.shbelow
我有我的 shell 脚本，myscript.sh在下面
#!/bin/sh
if [ = "-r" ]; then
echo "I am here"
fi
If I run with . myscript.sh -r, it works well with message I am here.
如果我使用. myscript.sh -r，它可以很好地处理 message I am here。
But if I just run with . myscript.sh, it complaints
但如果我只是跑. myscript.sh，它会抱怨
-bash: [: =: unary operator expected
-bash: [: =: unary operator expected
What's missing in my script?
我的脚本中缺少什么？
回答by Bhakti Gandhi
You would need to add quotes around $1.
您需要在 1 美元左右添加报价。
if [ "" = "-r" ]; then
echo "I am here"
fi
When $1 is empty you are getting if [ = "-r"] which is a syntax error.
当 $1 为空时，您会得到 if [ = "-r"] 这是一个语法错误。
回答by Slava Semushin
You have missed the quotes:
你错过了报价：
if [ "" = "-r" ]; then
