mirror of
https://github.com/LCTT/TranslateProject.git
synced 2024-12-26 21:30:55 +08:00
翻译完成
This commit is contained in:
zjon
parent
49b5586379
commit
d0222849f1
@ -1,250 +0,0 @@
|
||||
zjon Translating
|
||||
How To Debug a Bash Shell Script Under Linux or UNIX
|
||||
======
|
||||
From my mailbag:
|
||||
**I wrote a small hello world script. How can I Debug a bash shell scripts running on a Linux or Unix like systems?**
|
||||
It is the most common question asked by new sysadmins or Linux/UNIX user. Shell scripting debugging can be a tedious job (read as not easy). There are various ways to debug a shell script.
|
||||
|
||||
You need to pass the -x or -v argument to bash shell to walk through each line in the script.
|
||||
|
||||
[![How to debug a bash shell script on Linux or Unix][1]][1]
|
||||
|
||||
Let us see how to debug a bash script running on Linux and Unix using various methods.
|
||||
|
||||
### -x option to debug a bash shell script
|
||||
|
||||
Run a shell script with -x option.
|
||||
```
|
||||
$ bash -x script-name
|
||||
$ bash -x domains.sh
|
||||
```
|
||||
|
||||
### Use of set builtin command
|
||||
|
||||
Bash shell offers debugging options which can be turn on or off using the [set command][2]:
|
||||
|
||||
* **set -x** : Display commands and their arguments as they are executed.
|
||||
* **set -v** : Display shell input lines as they are read.
|
||||
|
||||
|
||||
|
||||
You can use above two command in shell script itself:
|
||||
```
|
||||
#!/bin/bash
|
||||
clear
|
||||
|
||||
# turn on debug mode
|
||||
set -x
|
||||
for f in *
|
||||
do
|
||||
file $f
|
||||
done
|
||||
# turn OFF debug mode
|
||||
set +x
|
||||
ls
|
||||
# more commands
|
||||
```
|
||||
|
||||
You can replace the [standard Shebang][3] line:
|
||||
`#!/bin/bash`
|
||||
with the following (for debugging) code:
|
||||
`#!/bin/bash -xv`
|
||||
|
||||
### Use of intelligent DEBUG function
|
||||
|
||||
First, add a special variable called _DEBUG. Set _DEBUG to 'on' when you need to debug a script:
|
||||
`_DEBUG="on"`
|
||||
|
||||
Put the following function at the beginning of the script:
|
||||
```
|
||||
function DEBUG()
|
||||
{
|
||||
[ "$_DEBUG" == "on" ] && $@
|
||||
}
|
||||
```
|
||||
|
||||
function DEBUG() { [ "$_DEBUG" == "on" ] && $@ }
|
||||
|
||||
Now wherever you need debugging simply use the DEBUG function as follows:
|
||||
`DEBUG echo "File is $filename"`
|
||||
OR
|
||||
```
|
||||
DEBUG set -x
|
||||
Cmd1
|
||||
Cmd2
|
||||
DEBUG set +x
|
||||
```
|
||||
|
||||
When done with debugging (and before moving your script to production) set _DEBUG to 'off'. No need to delete debug lines.
|
||||
`_DEBUG="off" # set to anything but not to 'on'`
|
||||
|
||||
Sample script:
|
||||
```
|
||||
#!/bin/bash
|
||||
_DEBUG="on"
|
||||
function DEBUG()
|
||||
{
|
||||
[ "$_DEBUG" == "on" ] && $@
|
||||
}
|
||||
|
||||
DEBUG echo 'Reading files'
|
||||
for i in *
|
||||
do
|
||||
grep 'something' $i > /dev/null
|
||||
[ $? -eq 0 ] && echo "Found in $i file"
|
||||
done
|
||||
DEBUG set -x
|
||||
a=2
|
||||
b=3
|
||||
c=$(( $a + $b ))
|
||||
DEBUG set +x
|
||||
echo "$a + $b = $c"
|
||||
```
|
||||
|
||||
Save and close the file. Run the script as follows:
|
||||
`$ ./script.sh`
|
||||
Output:
|
||||
```
|
||||
Reading files
|
||||
Found in xyz.txt file
|
||||
+ a=2
|
||||
+ b=3
|
||||
+ c=5
|
||||
+ DEBUG set +x
|
||||
+ '[' on == on ']'
|
||||
+ set +x
|
||||
2 + 3 = 5
|
||||
|
||||
```
|
||||
|
||||
Now set DEBUG to off (you need to edit the file):
|
||||
`_DEBUG="off"`
|
||||
Run script:
|
||||
`$ ./script.sh`
|
||||
Output:
|
||||
```
|
||||
Found in xyz.txt file
|
||||
2 + 3 = 5
|
||||
|
||||
```
|
||||
|
||||
Above is a simple but quite effective technique. You can also try to use DEBUG as an alias instead of function.
|
||||
|
||||
### Debugging Common Bash Shell Scripting Errors
|
||||
|
||||
Bash or sh or ksh gives various error messages on screen and in many case the error message may not provide detailed information.
|
||||
|
||||
#### Skipping to apply execute permission on the file
|
||||
|
||||
When you [write your first hello world bash shell script][4], you might end up getting an error that read as follows:
|
||||
`bash: ./hello.sh: Permission denied`
|
||||
Set permission using chmod command:
|
||||
```
|
||||
$ chmod +x hello.sh
|
||||
$ ./hello.sh
|
||||
$ bash hello.sh
|
||||
```
|
||||
|
||||
#### End of file unexpected Error
|
||||
|
||||
If you are getting an End of file unexpected error message, open your script file and and make sure it has both opening and closing quotes. In this example, the echo statement has an opening quote but no closing quote:
|
||||
```
|
||||
#!/bin/bash
|
||||
|
||||
|
||||
...
|
||||
....
|
||||
|
||||
|
||||
echo 'Error: File not found
|
||||
^^^^^^^
|
||||
missing quote
|
||||
```
|
||||
|
||||
Also make sure you check for missing parentheses and braces ({}):
|
||||
```
|
||||
#!/bin/bash
|
||||
.....
|
||||
[ ! -d $DIRNAME ] && { echo "Error: Chroot dir not found"; exit 1;
|
||||
^^^^^^^^^^^^^
|
||||
missing brace }
|
||||
...
|
||||
```
|
||||
|
||||
#### Missing Keywords Such As fi, esac, ;;, etc.
|
||||
|
||||
If you missed ending keyword such as fi or ;; you will get an error such as as "xxx unexpected". So make sure all nested if and case statements ends with proper keywords. See bash man page for syntax requirements. In this example, fi is missing:
|
||||
```
|
||||
#!/bin/bash
|
||||
echo "Starting..."
|
||||
....
|
||||
if [ $1 -eq 10 ]
|
||||
then
|
||||
if [ $2 -eq 100 ]
|
||||
then
|
||||
echo "Do something"
|
||||
fi
|
||||
|
||||
for f in $files
|
||||
do
|
||||
echo $f
|
||||
done
|
||||
|
||||
# note fi is missing
|
||||
```
|
||||
|
||||
#### Moving or editing shell script on Windows or Unix boxes
|
||||
|
||||
Do not create the script on Linux/Unix and move to Windows. Another problem is editing the bash shell script on Windows 10 and move/upload to Unix server. It will result in an error like command not found due to the carriage return (DOS CR-LF). You [can convert DOS newlines CR-LF to Unix/Linux format using][5] the following syntax:
|
||||
`dos2unix my-script.sh`
|
||||
|
||||
### Tip 1 - Send Debug Message To stderr
|
||||
|
||||
[Standard error][6] is the default error output device, which is used to write all system error messages. So it is a good idea to send messages to the default error device:
|
||||
```
|
||||
# Write error to stdout
|
||||
echo "Error: $1 file not found"
|
||||
#
|
||||
# Write error to stderr (note 1>&2 at the end of echo command)
|
||||
#
|
||||
echo "Error: $1 file not found" 1>&2
|
||||
```
|
||||
|
||||
### Tip 2 - Turn On Syntax Highlighting when using vim text editor
|
||||
|
||||
Most modern text editors allows you to set syntax highlighting option. This is useful to detect syntax and prevent common errors such as opening or closing quote. You can see bash script in different colors. This feature eases writing in a shell script structures and syntax errors are visually distinct. Highlighting does not affect the meaning of the text itself; it's made only for you. In this example, vim syntax highlighting is used for my bash script:
|
||||
[![How To Debug a Bash Shell Script Under Linux or UNIX Using Vim Syntax Highlighting Feature][7]][7]
|
||||
|
||||
### Tip 3 - Use shellcheck to lint script
|
||||
|
||||
[ShellCheck is a static analysis tool for shell scripts][8]. One can use it to finds bugs in your shell scripts. It is written in Haskell. You can find warnings and suggestions for bash/sh shell scripts with this tool. Let us see how to install and use ShellCheck on a Linux or Unix-like system to enhance your shell scripts, avoid errors and productivity.
|
||||
|
||||
|
||||
### About the author
|
||||
|
||||
Posted by:
|
||||
|
||||
The author is the creator of nixCraft and a seasoned sysadmin and a trainer for the Linux operating system/Unix shell scripting. He has worked with global clients and in various industries, including IT, education, defense and space research, and the nonprofit sector. Follow him on [Twitter][9], [Facebook][10], [Google+][11].
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://www.cyberciti.biz/tips/debugging-shell-script.html
|
||||
|
||||
作者：[Vivek Gite][a]
|
||||
译者：[译者ID](https://github.com/译者ID)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
[a]:https://www.cyberciti.biz
|
||||
[1]:https://www.cyberciti.biz/tips/wp-content/uploads/2007/01/How-to-debug-a-bash-shell-script-on-Linux-or-Unix.jpg
|
||||
[2]:https://bash.cyberciti.biz/guide/Set_command
|
||||
[3]:https://bash.cyberciti.biz/guide/Shebang
|
||||
[4]:https://www.cyberciti.biz/faq/hello-world-bash-shell-script/
|
||||
[5]:https://www.cyberciti.biz/faq/howto-unix-linux-convert-dos-newlines-cr-lf-unix-text-format/
|
||||
[6]:https://bash.cyberciti.biz/guide/Standard_error
|
||||
[7]:https://www.cyberciti.biz/media/new/tips/2007/01/bash-vim-debug-syntax-highlighting.png
|
||||
[8]:https://www.cyberciti.biz/programming/improve-your-bashsh-shell-script-with-shellcheck-lint-script-analysis-tool/
|
||||
[9]:https://twitter.com/nixcraft
|
||||
[10]:https://facebook.com/nixcraft
|
||||
[11]:https://plus.google.com/+CybercitiBiz
|
||||
@ -0,0 +1,246 @@
|
||||
如何在 Linux 或者 UNIX 下调试 Bash Shell 脚本
|
||||
======
|
||||
来自我的邮箱：
|
||||
**我写了一个你好世界的小脚本。我如何能调试运行在 Linux 或者类 UNIX 的系统上的 bash shell 脚本呢？**
|
||||
这是 Linux / Unix 系统管理员或新用户最常问的问题。shell 脚本调试可能是一项繁琐的工作（不容易阅读）。调试 shell 脚本有多种方法。
|
||||
|
||||
您需要传递 -X 或 -V 参数，以在 bash shell 中浏览每行代码。
|
||||
|
||||
[![如何在 Linux 或者 UNIX 下调试 Bash Shell 脚本][1]][1]
|
||||
|
||||
让我们看看如何使用各种方法调试 Linux 和 UNIX 上运行的脚本。
|
||||
|
||||
```
|
||||
### -x 选项来调试脚本
|
||||
|
||||
用 -x 选项来运行脚本
|
||||
```
|
||||
$ bash -x script-name
|
||||
$ bash -x domains.sh
|
||||
```
|
||||
|
||||
### 使用 set 内置命令
|
||||
|
||||
bash shell 提供调试选项，可以打开或关闭使用 [set 命令][2]：
|
||||
|
||||
* **set -x** : 显示命令及其执行时的参数。
|
||||
* **set -v** : 显示 shell 输入行作为它们读取的
|
||||
|
||||
可以在shell脚本本身中使用上面的两个命令：
|
||||
```
|
||||
#!/bin/bash
|
||||
clear
|
||||
|
||||
# turn on debug mode
|
||||
set -x
|
||||
for f in *
|
||||
do
|
||||
file $f
|
||||
done
|
||||
# turn OFF debug mode
|
||||
set +x
|
||||
ls
|
||||
# more commands
|
||||
```
|
||||
|
||||
你可以代替 [标准 Shebang][3] 行：
|
||||
`#!/bin/bash`
|
||||
用一下代码（用于调试）：
|
||||
`#!/bin/bash -xv`
|
||||
|
||||
### 使用智能调试功能
|
||||
|
||||
首先添加一个叫做 _DEBUG 的特殊变量。当你需要调试脚本的时候，设置 _DEBUG 为 'on'：
|
||||
`_DEBUG="on"`
|
||||
|
||||
|
||||
在脚本的开头放置以下函数：
|
||||
```
|
||||
function DEBUG()
|
||||
{
|
||||
[ "$_DEBUG" == "on" ] && $@
|
||||
}
|
||||
```
|
||||
|
||||
function DEBUG() { [ "$_DEBUG" == "on" ] && $@ }
|
||||
|
||||
现在，只要你需要调试，只需使用 DEBUG 函数如下：
|
||||
`DEBUG echo "File is $filename"`
|
||||
或者
|
||||
```
|
||||
DEBUG set -x
|
||||
Cmd1
|
||||
Cmd2
|
||||
DEBUG set +x
|
||||
```
|
||||
|
||||
当调试完（在移动你的脚本到生产环境之前）设置 _DEBUG 为 'off'。不需要删除调试行。
|
||||
`_DEBUG="off" # 设置为非 'on' 的任何字符`
|
||||
|
||||
|
||||
示例脚本：
|
||||
```
|
||||
#!/bin/bash
|
||||
_DEBUG="on"
|
||||
function DEBUG()
|
||||
{
|
||||
[ "$_DEBUG" == "on" ] && $@
|
||||
}
|
||||
|
||||
DEBUG echo 'Reading files'
|
||||
for i in *
|
||||
do
|
||||
grep 'something' $i > /dev/null
|
||||
[ $? -eq 0 ] && echo "Found in $i file"
|
||||
done
|
||||
DEBUG set -x
|
||||
a=2
|
||||
b=3
|
||||
c=$(( $a + $b ))
|
||||
DEBUG set +x
|
||||
echo "$a + $b = $c"
|
||||
```
|
||||
|
||||
保存并关闭文件。运行脚本如下：
|
||||
`$ ./script.sh`
|
||||
输出:
|
||||
```
|
||||
Reading files
|
||||
Found in xyz.txt file
|
||||
+ a=2
|
||||
+ b=3
|
||||
+ c=5
|
||||
+ DEBUG set +x
|
||||
+ '[' on == on ']'
|
||||
+ set +x
|
||||
2 + 3 = 5
|
||||
|
||||
```
|
||||
|
||||
现在设置 DEBUG 为关闭（你需要编辑文件）：
|
||||
`_DEBUG="off"`
|
||||
运行脚本:
|
||||
`$ ./script.sh`
|
||||
输出:
|
||||
```
|
||||
Found in xyz.txt file
|
||||
2 + 3 = 5
|
||||
|
||||
```
|
||||
|
||||
以上是一个简单但非常有效的技术。还可以尝试使用 DEBUG 作为别名替代函数。
|
||||
|
||||
### 调试 Bash Shell 的常见错误
|
||||
|
||||
Bash 或者 sh 或者 ksh 在屏幕上给出各种错误信息，在很多情况下，错误信息可能不提供详细的信息。
|
||||
|
||||
#### 跳过在文件上应用执行权限
|
||||
When you [write your first hello world bash shell script][4], you might end up getting an error that read as follows:
|
||||
当你 [编写你的第一个 hello world 脚本][4],您可能会得到一个错误，如下所示：
|
||||
`bash: ./hello.sh: Permission denied`
|
||||
设置权限使用 chmod 命令:
|
||||
```
|
||||
$ chmod +x hello.sh
|
||||
$ ./hello.sh
|
||||
$ bash hello.sh
|
||||
```
|
||||
|
||||
#### 文件结束时发生意外的错误
|
||||
|
||||
如果您收到文件结束意外错误消息，请打开脚本文件，并确保它有打开和关闭引号。在这个例子中，echo 语句有一个开头引号，但没有结束引号：
|
||||
```
|
||||
#!/bin/bash
|
||||
|
||||
|
||||
...
|
||||
....
|
||||
|
||||
|
||||
echo 'Error: File not found
|
||||
^^^^^^^
|
||||
missing quote
|
||||
```
|
||||
|
||||
还要确保你检查缺少的括号和大括号 ({}):
|
||||
```
|
||||
#!/bin/bash
|
||||
.....
|
||||
[ ! -d $DIRNAME ] && { echo "Error: Chroot dir not found"; exit 1;
|
||||
^^^^^^^^^^^^^
|
||||
missing brace }
|
||||
...
|
||||
```
|
||||
|
||||
#### 丢失像 fi，esac，;; 等关键字。
|
||||
如果你缺少了结尾的关键字，如 fi 或 ;; 你会得到一个错误，如 “XXX 意外”。因此，确保所有嵌套的 if 和 case 语句以适当的关键字结束。有关语法要求的页面。在本例中，缺少 fi：
|
||||
```
|
||||
#!/bin/bash
|
||||
echo "Starting..."
|
||||
....
|
||||
if [ $1 -eq 10 ]
|
||||
then
|
||||
if [ $2 -eq 100 ]
|
||||
then
|
||||
echo "Do something"
|
||||
fi
|
||||
|
||||
for f in $files
|
||||
do
|
||||
echo $f
|
||||
done
|
||||
|
||||
# 注意 fi 已经丢失
|
||||
```
|
||||
|
||||
#### 在 Windows 或 UNIX 框中移动或编辑 shell 脚本
|
||||
|
||||
不要在 Linux 上创建脚本并移动到 Windows。另一个问题是编辑 Windows 10上的 shell 脚本并将其移动到 UNIX 服务器上。这将导致一个错误的命令没有发现由于回车返回（DOS CR-LF）。你可以 [将 DOS 换行转换为 CR-LF 的Unix/Linux 格式][5] 使用下列命令：
|
||||
`dos2unix my-script.sh`
|
||||
|
||||
### 提示1 - 发送调试信息输出到标准错误
|
||||
[标准错误] 是默认错误输出设备，用于写所有系统错误信息。因此，将消息发送到默认的错误设备是个好主意：
|
||||
```
|
||||
# 写错误到标准输出
|
||||
echo "Error: $1 file not found"
|
||||
#
|
||||
# 写错误到标准错误（注意 1>&2 在 echo 命令末尾）
|
||||
#
|
||||
echo "Error: $1 file not found" 1>&2
|
||||
```
|
||||
|
||||
### 提示2 - 在使用 vim 文本编辑器时，打开语法高亮。
|
||||
大多数现代文本编辑器允许设置语法高亮选项。这对于检测语法和防止常见错误如打开或关闭引号非常有用。你可以在不同的颜色中看到。这个特性简化了 shell 脚本结构中的编写，语法错误在视觉上截然不同。强调不影响文本本身的意义，它只为你编写。在这个例子中，我的脚本使用了 vim 语法高亮：
|
||||
[!如何调试 Bash Shell 脚本，在 Linux 或者 UNIX 使用 Vim 语法高亮特性][7]][7]
|
||||
|
||||
### 提示3 - 使用 shellcheck 检查脚本
|
||||
[shellcheck 是一个用于静态分析 shell 脚本的工具][8]。可以使用它来查找 shell 脚本中的错误。这是用 Haskell 编写的。您可以使用这个工具找到警告和建议。让我们看看如何在 Linux 或 类UNIX 系统上安装和使用 shellcheck 来改善你的 shell 脚本，避免错误和高效。
|
||||
|
||||
### 关于作者
|
||||
发表者：
|
||||
|
||||
作者是 nixCraft 创造者，一个经验丰富的系统管理员和一个练习 Linux 操作系统/ UNIX shell 脚本的教练。他曾与全球客户和各种行业，包括 IT，教育，国防和空间研究，以及非营利部门。跟随他 [推特][9]，[脸谱网][10]，[谷歌+ ][11]。
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://www.cyberciti.biz/tips/debugging-shell-script.html
|
||||
|
||||
作者：[Vivek Gite][a]
|
||||
译者：[zjon](https://github.com/zjon)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
[a]:https://www.cyberciti.biz
|
||||
[1]:https://www.cyberciti.biz/tips/wp-content/uploads/2007/01/How-to-debug-a-bash-shell-script-on-Linux-or-Unix.jpg
|
||||
[2]:https://bash.cyberciti.biz/guide/Set_command
|
||||
[3]:https://bash.cyberciti.biz/guide/Shebang
|
||||
[4]:https://www.cyberciti.biz/faq/hello-world-bash-shell-script/
|
||||
[5]:https://www.cyberciti.biz/faq/howto-unix-linux-convert-dos-newlines-cr-lf-unix-text-format/
|
||||
[6]:https://bash.cyberciti.biz/guide/Standard_error
|
||||
[7]:https://www.cyberciti.biz/media/new/tips/2007/01/bash-vim-debug-syntax-highlighting.png
|
||||
[8]:https://www.cyberciti.biz/programming/improve-your-bashsh-shell-script-with-shellcheck-lint-script-analysis-tool/
|
||||
[9]:https://twitter.com/nixcraft
|
||||
[10]:https://facebook.com/nixcraft
|
||||
[11]:https://plus.google.com/+CybercitiBiz
|
||||
|
||||
|
||||
Loading…
Reference in New Issue
Block a user