linux►程序

sed

参数

-E

  • 使用扩展语法
  • 扩展语法和基础语法区别主要在于少量字符的差异，?、+、()、{}，在基础语法中需要转义来作为特殊字符；相反，在扩展语法中，需要转义以匹配无特殊含义的文本字符

示例

替换

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$ cat msg
{
'localhost' => ['domain_name' => 'default', 'domain_type' => 'mobile'],
}

# 替换文件内容并打印
$ sed '/localhost/p; s/localhost/dev.ops/' msg
{
'localhost' => ['domain_name' => 'default', 'domain_type' => 'mobile'],
'dev.ops' => ['domain_name' => 'default', 'domain_type' => 'mobile'],
}

# 替换文件内容并将输出重定向到新文件
$ sed '/localhost/p; s/localhost/dev.ops/' msg > new_msg
$ cat new_msg
{
'localhost' => ['domain_name' => 'default', 'domain_type' => 'mobile'],
'dev.ops' => ['domain_name' => 'default', 'domain_type' => 'mobile'],
}
# 源文件并未更改
$ cat msg
{
'localhost' => ['domain_name' => 'default', 'domain_type' => 'mobile'],
}

# 在源文件修改并保存源文件至备份文件
$ sed -i 'msg_backup' '/localhost/p; s/localhost/dev.ops/' msg
$ ls
msg		msgmsg_backup	new_msg
# 打印源文件备份
$ cat msgmsg_backup
{
'localhost' => ['domain_name' => 'default', 'domain_type' => 'mobile'],
}
# 打印源文件
$ cat msg
{
'localhost' => ['domain_name' => 'default', 'domain_type' => 'mobile'],
'dev.ops' => ['domain_name' => 'default', 'domain_type' => 'mobile'],
}

# 直接修改源文件并且不保存备份
$ sed -i '/localhost/p; s/localhost/dev.worker/' msgmsg_backup
# $ sed -i '' '/localhost/p; s/localhost/dev.worker/' msgmsg_backup	# os x
$ cat msgmsg_backup
{
'localhost' => ['domain_name' => 'default', 'domain_type' => 'mobile'],
'dev.worker' => ['domain_name' => 'default', 'domain_type' => 'mobile'],
}

$ ls
msg		msgmsg_backup	new_msg

#### Other Examples
## 正则替换
$ cat script/config.sh
workers=6666
threads_compute=10
threads=101
$ sed -i "s/workers=[0-9]*/workers=9/" ./script/config.sh
$ cat script/config.sh
workers=9
threads_compute=10
threads=101

# group
sed -i "s/workers=([0-9]+)/\1/" /path/to/file

替换子串

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sed -i 's/head/heap/g' Heap.cpp
# sed -i '' 's/head/heap/g' Heap.cpp	# 不保留文件备份

替换前复制行

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sed '/localhost/p; s/localhost/dev.ops/' FILENAME

group 替换

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$ echo "hello wii." | sed -E 's/hello ([a-z]+).*/\1/'
wii
# OR
$ echo "hello wii." | sed 's/hello \([a-z]\+\).*/\1/'   # 注: 不同系统，+ 号的行为可能不一致，这条命令在 big sur (mac os) 中无法输出预想结果
wii

以上有个问题，如果为匹配到数据，最终打印原始数据，比如。

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$ echo "hello wii." | sed -E 's/hi ([a-z]+).*/\1/'
hello wii.

/patt/!d;s//repl/可实现匹配不到打印空，如下。

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$ echo "hello wii." | sed -E '/hi ([a-z]+).*/!d;s//\1/' 
# empty

问题

sed: 1: ... : extra characters at the end of H command

  • edit in place on OSX without keeping a backup, use -i '':

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    sed -i '' -e '/localhost/p; s/localhost/dev.ops/' FILENAME

参考