bash 脚本中的 mkdir 错误

发布于 2024-08-31 01:20:09 字数 553 浏览 8 评论 0原文

以下是我在 Windows 上的 cygwin 下运行的 bash 脚本的片段：

deployDir=/cygdrive/c/Temp/deploy

timestamp=`date +%Y-%m-%d_%H:%M:%S`
deployDir=${deployDir}/$timestamp

if [ ! -d "$deployDir" ]; then
    echo "making dir $deployDir"
    mkdir -p $deployDir
fi

这会产生如下输出：

making dir /cygdrive/c/Temp/deploy/2010-04-30_11:47:58
mkdir: missing operand
Try `mkdir --help' for more information.

但是，如果我输入 /cygdrive/c/Temp/deploy/2010-04-30_11:47： 58 在命令行上它成功了，为什么相同的命令在脚本中不起作用？

谢谢，大学教师

原文

The following is a fragment of a bash script that I'm running under cygwin on Windows:

deployDir=/cygdrive/c/Temp/deploy

timestamp=`date +%Y-%m-%d_%H:%M:%S`
deployDir=${deployDir}/$timestamp

if [ ! -d "$deployDir" ]; then
    echo "making dir $deployDir"
    mkdir -p $deployDir
fi

This produces output such as:

making dir /cygdrive/c/Temp/deploy/2010-04-30_11:47:58
mkdir: missing operand
Try `mkdir --help' for more information.

However, if I type /cygdrive/c/Temp/deploy/2010-04-30_11:47:58 on the command-line it succeeds, why does the same command not work in the script?

Thanks,
Don

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柠北森屋 2024-09-07 01:20:09

更改：

mkdir -p $deploydir

与

mkdir -p "$deployDir"

大多数 Unix shell（甚至可能是所有 shell）一样，Bourne（再次）Shell (sh/bash) 区分大小写。 dir var 在任何地方都被称为 deployDir（混合大小写），除了 mkdir 命令，它被称为 deploydir（全部小写）。由于 deploydir （全部小写）被认为是与 deployDir （混合大小写）不同的变量，并且 deplydir （全部小写）从未有过值分配给它时，deploydir 的值（全部小写）为空字符串 ("")。

如果没有引号 (mkdir $deploydir)，该行实际上会变为 mkdir（只是没有所需操作数的命令），因此会出现错误 mkdir: Missing operand代码>.

使用引号 (mkdir "$deploydir")，该行实际上变为 mkdir "" （使用空字符串的非法目录名创建目录的命令），因此错误mkdir：无法创建目录'。

如果目标目录名称包含空格，建议使用带引号的形式 (mkdir "$deployDir")。

Change:

mkdir -p $deploydir

mkdir -p "$deployDir"

Like most Unix shells (maybe even all of them), Bourne (Again) Shell (sh/bash) is case-sensitive. The dir var is called deployDir (mixed-case) everywhere except for the mkdir command, where it is called deploydir (all lowercase). Since deploydir (all lowercase) is a considered distinct variable from deployDir (mixed-case) and deplydir (all lowercase) has never had a value assigned to it, the value of deploydir (all lowercase) is empty string ("").

Without the quotes (mkdir $deploydir), the line effectively becomes mkdir (just the command without the required operand), thus the error mkdir: missing operand.

With the quotes (mkdir "$deploydir"), the line effectively becomes mkdir "" (the command to make a directory with the illegal directory name of empty string), thus the error mkdir: cannot create directory'.

Using the form with quotes (mkdir "$deployDir") is recommended in case the target directory name includes spaces.

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