用于自动克隆 git 源的 Linux Shell 脚本

Question 1

这个脚本有很多问题。首先，让我们检查一下类似脚本的工具shellcheck对此有何说明：lintshell

$ ~/.cabal/bin/shellcheck git-installer.sh

In git-installer.sh line 17:
if [$ans == $back]; then
^-- SC1009: The mentioned parser error was in this if expression.
   ^-- SC1035: You need a space after the [ and before the ].
   ^-- SC1073: Couldn't parse this test expression.
                  ^-- SC1020: You need a space before the ].
                  ^-- SC1072: Missing space before ]. Fix any mentioned problems and try again.

这是错误的根源以及应该采取哪些措施来避免错误的建议。您需要在每个方括号之前和之后添加一个空格，以便您的脚本如下所示：

#!/bin/sh
mkdir /home/my-username/git-sources
cd home/my-username/git-sources

read gitsource

git clone $gitsource

echo "Please choose from the options bellow"

echo "1)Go back to your working directory"
echo "2) GO to the 'git-sources' folder"

read ans
back="1"
stay="2"
if [ $ans == $back ]; then
      cd -
elif [ $ans == $stay ]; then
      cd /home/my-username/git-sources
fi

但shellcheck还是不高兴：

$ ~/.cabal/bin/shellcheck git-installer.sh

In git-installer.sh line 3:
cd home/my-username/git-sources
^-- SC2164: Use cd ... || exit in case cd fails.


In git-installer.sh line 5:
read gitsource
^-- SC2162: read without -r will mangle backslashes.


In git-installer.sh line 7:
git clone $gitsource
          ^-- SC2086: Double quote to prevent globbing and word splitting.


In git-installer.sh line 14:
read ans
^-- SC2162: read without -r will mangle backslashes.


In git-installer.sh line 17:
if [ $ans == $back ]; then
     ^-- SC2086: Double quote to prevent globbing and word splitting.
          ^-- SC2039: In POSIX sh, == in place of = is undefined.


In git-installer.sh line 18:
      cd -
      ^-- SC2164: Use cd ... || exit in case cd fails.


In git-installer.sh line 19:
elif [ $ans == $stay ]; then
       ^-- SC2086: Double quote to prevent globbing and word splitting.
            ^-- SC2039: In POSIX sh, == in place of = is undefined.


In git-installer.sh line 20:
      cd /home/my-username/git-sources
      ^-- SC2164: Use cd ... || exit in case cd fails.

除了修复报告的所有错误和警告之外，shellcheck我们还可以进一步改进此脚本。

您可以使用简单明了的"$HOME"代替， /home/my-username以便该脚本适用于每个用户。

另请注意，mkdir仅当目录尚不存在时才应在顶部完成，File exists否则我们将收到错误。

如果能向用户打印一些提示，告诉他们我们期望他们输入，那就太好了。

另请注意，为了按照cd您可能想象的方式运行，您必须使用source此脚本而不是运行它。话虽这么说，我们应该通过取消设置我们根据需要创建的变量来整理用户环境。

总结起来应该是：

#!/bin/sh

if [ ! -d "$HOME"/git-sources ]; then
    mkdir "$HOME"/git-sources
fi

cd "$HOME"/git-sources || { printf "cd failed, exiting\n" >&2;  return 1; }

printf "Gitsource: "
read -r gitsource

git clone "$gitsource"

unset gitsource

echo "Please choose from the options bellow"

echo "1) Go back to your working directory"
echo "2) Go to the 'git-sources' folder"

read -r ans
back="1"
stay="2"
if [ "$ans" = "$back" ]; then
      cd - || { printf "cd failed, exiting\n" >&2; unset ans; return 1; }
elif [ "$ans" = "$stay" ]; then
      cd "$HOME"/git-sources || { printf "cd failed, exiting\n" >&2; unset ans; return 1; }
fi

unset ans

来源：

$ . git-installer.sh
Gitsource: https://github.com/antirez/linenoise
Cloning into 'linenoise'...
remote: Counting objects: 396, done.
remote: Total 396 (delta 0), reused 0 (delta 0), pack-reused 396
Receiving objects: 100% (396/396), 114.69 KiB | 0 bytes/s, done.
Resolving deltas: 100% (232/232), done.
Checking connectivity... done.
Please choose from the options bellow
1) Go back to your working directory
2) Go to the 'git-sources' folder
2
$ pwd
/home/ja/git-sources
$ ls -Al
total 4
drwxr-xr-x 3 ja users 4096 Dec 25 22:48 linenoise

Answer