在bash脚本错误的mkdir [英] mkdir error in bash script

问题描述

下面是我在Cygwin的Windows上运行bash脚本的一个片段：

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

这产生的输出，例如：

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

不过，如果我键入 / cygdrive / C /温度/部署/ 2010-04-30_11：47：58 在命令行成功，为什么用相同的命令脚本不工作？

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?

谢谢，
唐

推荐答案

修改

mkdir -p $deploydir

到

mkdir -p "$deployDir"

最喜欢的Unix外壳（甚至全部），伯恩（再次）壳牌（SH / bash）的是区分大小写的。该目录VAR被称为 deployDir （混合大小写）处处除的mkdir 命令，其中它被称为 deploydir （全部小写）。由于 deploydir （全部小写）为 deployDir A认为是不同的变量（混合大小写）和 deplydir （全部小写）从来没有分配给它的价值，价值 deploydir （全部小写）为空字符串（）

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 ("").

如果没有引号（的mkdir $ deploydir ），该行有效地成为的mkdir （只是没有按规定命令操作数），因此误差的mkdir：缺少操作数

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

使用引号（的mkdir$ deploydir），该行有效地成为的mkdir（命令使空字符串非法目录名称的目录），因此误差的mkdir：无法创建目录

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'.

使用带引号（的mkdir$ deployDir）的形式的情况下，建议在目标目录名称中包含空格。

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

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