为什么 shell 解释单引号内的字符？
我正在使用 bash shell
$cat test
a --b
$grep '--b' test
grep: option `--b' is ambiguous
Usage: grep [OPTION]... PATTERN [FILE]...
Try `grep --help' for more information.
$grep "--b" test
grep: option `--b' is ambiguous
Usage: grep [OPTION]... PATTERN [FILE]...
Try `grep --help' for more information.
$grep '\-\-b' test
a --b
经典的 shell 脚本书籍第 7 章“输入和输出、文件和命令评估”第 7.7 节引用说
“单引号强制 shell 按字面意思处理一对引号之间的所有内容”。
那么为什么上面的单引号不起作用呢？
I am using bash shell
$cat test
a --b
$grep '--b' test
grep: option `--b' is ambiguous
Usage: grep [OPTION]... PATTERN [FILE]...
Try `grep --help' for more information.
$grep "--b" test
grep: option `--b' is ambiguous
Usage: grep [OPTION]... PATTERN [FILE]...
Try `grep --help' for more information.
$grep '\-\-b' test
a --b
The classic shell scripting book in chapter 7 "Input and Output,Files, and Command Evaluation" in section 7.7 Quoting says that
"Single quotes force the shell to treat everything between the pair of quotes literally".
Then why is single quotes not working above?
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shell按字面意思对待它们。但 shell 不负责应用程序如何对待它们。由应用程序决定如何处理作为参数传递的
--b。The shell is treating them literally. But the shell is not responsible for how the application treats them. It is up to the application to decide how it wants to handle the
--bpassed as an argument.大多数 gnu 实用程序都会忽略
--之后的--options，因此您可能需要执行grep -- --b test。既然您标记了您的问题linux，那么您很可能拥有 gnu grep。Most of gnu utilities ignore
--optionsafter--, so you may want to do agrep -- --b testinstead. And since you tag your questionlinux, chances are you have gnu grep.