sed 命令的用法


s e d
是一个非交互性文本流编辑器。它编辑文件或标准输入导出的文本拷贝。

QUOTE:

" 抽取域。
"
匹配正则表达式。
"
比较域。
"
增加、附加、替换。
"
基本的s e d命令和一行脚本。


可以在命令行输入s e d命令,也可以在一个文件中写入命令,然后调用s e d,这与a w k基本相同。使用s e d需要记住的一个重要事实是,无论命令是什么, s e d并不与初始化文件打交道,它操作的只是一个拷贝,然后所有的改动如果没有重定向到一个文件,将输出到屏幕。

因为s e d是一个非交互性编辑器,必须通过行号或正则表达式指定要改变的文本行。
本文介绍s e d用法和功能。本章大多编写的是一行命令和小脚本。这样做可以慢慢加深对s e d用法的了解,取得宝贵的经验,以便最终自己编出大的复杂s e d脚本。
g r e pa w k一样, s e d是一种重要的文本过滤工具,或者使用一行命令或者使用管道与g r e pa w k相结合。

1 sed
怎样读取数据

s e d
从文件的一个文本行或从标准输入的几种格式中读取数据,将之拷贝到一个编辑缓冲区,然后读命令行或脚本的第一条命令,并使用这些命令查找模式或定位行号编辑它。重复此过程直到命令结束。

2
调用sed

调用s e d有三种方式:在命令行键入命令;将s e d命令插入脚本文件,然后调用s e d;将s e d命令插入脚本文件,并使s e d脚本可执行。

使用s e d命令行格式为:

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CODE:

sed [选项] s e d命令输入文件。


记住在命令行使用s e d命令时,实际命令要加单引号。s e d也允许加双引号。

使用s e d脚本文件,格式为:

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CODE:

sed [选项] -f sed脚本文件输入文件


要使用第一行具有s e d命令解释器的s e d脚本文件,其格式为:

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CODE:

s e d脚本文件[选项] 输入文件


不管是使用s h e l l命令行方式或脚本文件方式,如果没有指定输入文件, s e d从标准输入中接受输入,一般是键盘或重定向结果。

QUOTE:

s e d选项如下:
n
不打印;s e d不写编辑行到标准输出,缺省为打印所有行(编辑和未编辑)。p命令可以用来打印编辑行。
c
下一命令是编辑命令。使用多项编辑时加入此选项。如果只用到一条s e d命令,此选项无用,但指定它也没有关系。
f
如果正在调用s e d脚本文件,使用此选项。此选项通知s e d一个脚本文件支持所有的s e d命令,例如:sed -f myscript.sed input_file,这里m y s c r i p t . s e d即为支持s e d命令的文件。


2.1
保存sed输出
由于不接触初始化文件,如果想要保存改动内容,简单地将所有输出重定向到一个文件即可。下面的例子重定向s e d命令的所有输出至文件‘ m y o u t f i l e’,当对结果很满意时使用这种方法。

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CODE:

$sed 'some-sed-commands' input-file > myoutfile


2.2
使用sed在文件中查询文本的方式
s e d
浏览输入文件时,缺省从第一行开始,有两种方式定位文本:

QUOTE:

1) 使用行号,可以是一个简单数字,或是一个行号范围。
2 )
使用正则表达式


下面是使用s e d定位文本的一些方式。

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CODE:

x x为一行号,如1
x , y
表示行号范围从xy,如25表示从第2行到第5
/ p a t t e r n /
查询包含模式的行。例如/ d i s k //[a-z]/
/ p a t t e r n / p a t t e r n /
查询包含两个模式的行。例如/ d i s k / d i s k s /
p a t t e r n / , x
在给定行号上查询包含模式的行。如/ r i b b o n / , 3
x , / p a t t e r n /
通过行号和模式查询匹配行。3 . / v d u /
x , y !
查询不包含指定行号xy的行。1 , 2 !


2.3
基本sed编辑命令

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CODE:

sed编辑命令
p
打印匹配行
=
显示文件行号
a \
在定位行号后附加新文本信息
i \
在定位行号后插入新文本信息
d
删除定位行
c \
用新文本替换定位文本
s
使用替换模式替换相应模式
r
从另一个文件中读文本
w
写文本到一个文件
q
第一个模式匹配完成后推出或立即推出
l
显示与八进制A S C I I代码等价的控制字符
{ }
在定位行执行的命令组
n
从另一个文件中读文本下一行,并附加在下一行
g
将模式2粘贴到/pattern n/
y
传送字符
n
延续到下一输入行;允许跨行的模式匹配语句


sed
和正则表达式

s e d
识别任何基本正则表达式和模式及其行匹配规则。记住规则之一是:如果要定位一特殊字符,必须使用( \)屏蔽其特殊含义

 

s e d例子中使用下述文本文件q u o t e . t x t

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CODE:

[sam@Linux_chenwy sam]$ cat quote.txt
The honeysuckle band played all night long for only $90.
It was an evening of splendid music and company.
Too bad the disco floor fell through at 23:00.
The local nurse Miss P.Neave was in attendance.


1
使用print)显示行
只打印第二行,用-n

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CODE:

[sam@Linux_chenwy sam]$ sed -n '2p' quote.txt
It was an evening of splendid music and company.


2
打印范围
可以指定行的范围,现打印13行,用逗号分隔行号。

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CODE:

[sam@Linux_chenwy sam]$ sed -n '1,3p' quote.txt
The honeysuckle band played all night long for only $90.
It was an evening of splendid music and company.
Too bad the disco floor fell through at 23:00.


3
打印模式
假定要匹配单词N e a v e,并打印此行,方法如下。使用模式/ p a t t e r n /格式,这里为/ N e a v e /

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CODE:

[sam@Linux_chenwy sam]$ sed -n '/The/p' quote.txt
The honeysuckle band played all night long for only $90.
The local nurse Miss P.Neave was in attendance.


4
使用模式和行号进行查询
可以将行号和模式结合使用。假定要改动文件q u o t e . t x t最后一行中的单词t h e,使用s e d查询t h e,返回两行:

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CODE:

[sam@Linux_chenwy sam]$ sed -n '/The/p' quote.txt
The honeysuckle band played all night long for only $90.
The local nurse Miss P.Neave was in attendance.


使用模式与行号的混合方式可以剔除第一行,格式为l i n e _ n u m b e r, / p a t t e r n /。逗号用来分隔行号与模式开始部分。为达到预期结果,使用4 , / t h e /。意即只在第四行查询模式t h e,命令如下:

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CODE:

[sam@Linux_chenwy sam]$ sed -n '4,/The/p' quote.txt
The local nurse Miss P.Neave was in attendance.


上面有错,其实是把第四行后的都打出来了
这个模式应该哪果指定行找不到符合条件的,就从下一行开始查找,直到找到为止,并把,找到行之前的全部打打印出来。
如果指定行本身就符合条伯,把本行及后面的行的全部打印出来


5
匹配元字符
匹配元字符$前,必须使用反斜线\屏蔽其特殊含义。模式为/\$/ p

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CODE:

[sam@Linux_chenwy sam]$ sed -n '/\$/p' quote.txt
The honeysuckle band played all night long for only $90.


6
显示整个文件
要打印整个文件,只需将行范围设为第一行到最后一行1 , $$意为最后一行。

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CODE:

[sam@Linux_chenwy sam]$ sed -n '1,$p' quote.txt
The honeysuckle band played all night long for only $90.
It was an evening of splendid music and company.
Too bad the disco floor fell through at 23:00.
The local nurse Miss P.Neave was in attendance.


7
任意字符
匹配任意字母,后跟任意字母的0次或多次重复,并以i n g结尾,模式为/ . * i n g /。可以使用这个模式查询以i n g结尾的任意单词。

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CODE:

[sam@Linux_chenwy sam]$ sed -n '/.*ing/p' quote.txt
It was an evening of splendid music and company.


8
首行
要打印文件第一行,使用行号:

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CODE:

[sam@Linux_chenwy sam]$ sed -n '1p' quote.txt
The honeysuckle band played all night long for only $90.


9
最后一行
要打印最后一行,使用$$是代表最后一行的元字符。

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CODE:

[sam@Linux_chenwy sam]$ sed -n '$p' quote.txt
The local nurse Miss P.Neave was in attendance.


10
打印行号
要打印行号,使用等号=。打印模式匹配的行号,使用格式/ p a t t e r n / =

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CODE:

[sam@Linux_chenwy sam]$ sed -e '/music/=' quote.txt
The honeysuckle band played all night long for only $90.
2
It was an evening of splendid music and company.
Too bad the disco floor fell through at 23:00.
The local nurse Miss P.Neave was in attendance.


整个文件都打印出来,并且匹配行打印了行号。如果只关心实际行号,使用- e选项。

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CODE:

[sam@Linux_chenwy sam]$ sed -n '/music/=' quote.txt
2


如果只打印行号及匹配行,必须使用两个s e d命令,并使用e选项。第一个命令打印模式匹配行,第二个使用=选项打印行号,格式为sed -n -e /pattern/p -e /pattern/=

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CODE:

[sam@Linux_chenwy sam]$ sed -n -e '/music/p' -e '/music/='  quote.txt
It was an evening of splendid music and company.
2

 


11 附加文本

要附加文本,使用符号a \,可以将指定文本一行或多行附加到指定行。如果不指定文本放置位置, s e d缺省放在每一行后面。附加文本时不能指定范围,只允许一个地址模式。文本附加操作时,结果输出在标准输出上。注意它不能被编辑,因为s e d执行时,首先将文件的一行文本拷贝至缓冲区,在这里s e d编辑命令执行所有操作(不是在初始文件上),因为文本直接输出到标准输出,s e d并无拷贝。
要想在附加操作后编辑文本,必须保存文件,然后运行另一个s e d命令编辑它。这时文件的内容又被移至缓冲区。
附加操作格式如下:

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CODE:

[address]a\
text\
text\
......
text


地址指定一个模式或行号,定位新文本附加位置。a\ 通知s e da \后的文本进行实际附加操作。观察格式,注意每一行后面有一斜划线,这个斜划线代表换行。s e d执行到这儿,将创建一新行,然后插入下一文本行。最后一行不加斜划线, s e d假定这是附加命令结尾。

当附加或插入文本或键入几个s e d命令时,可以利用辅助的s h e l l提示符以输入多行命令。当附加或插入文本或键入几个s e d命令时,可以利用辅助的s h e l l提示符以输入多行命令。


创建sed脚本文件

创建脚本文件a p p e n d . s e d
第一行是s e d命令解释行。脚本在这一行查找s e d以运行命令,这里定位在/ b i n
第二行以/ c o m p a n y /开始,这是附加操作起始位置。a \通知s e d这是一个附加操作,首先应插入一个新行。
第三行是附加操作要加入到拷贝的实际文本。
输出显示附加结果。如果要保存输出,重定向到一个文件。

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CODE:

[sam@chenwy sam]$ cat append.sed
#!/bin/sed -f
/company/ a\
Then suddenly it happed.


保存它,增加可执行权限,运行

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CODE:

[sam@chenwy sam]chmod u+x append.sed
[sam@chenwy sam]$ ./append.sed quote.txt
The honeysuckle band played all night long for only $90.
It was an evening of splendid music and company.
Then suddenly it happed.
Too bad the disco floor fell through at 23:00.
The local nurse Miss P.Neave was in attendance.


或直接用命令行:

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CODE:

[sam@chenwy sam]$ sed "/company/a\Then suddenly it happened." quote.txt
The honeysuckle band played all night long for only $90.
It was an evening of splendid music and company.
Then suddenly it happened.
Too bad the disco floor fell through at 23:00.
The local nurse Miss P.Neave was in attendance.


[sam@chenwy sam]$ sed "/company/i\utter confusion followed." quote.txt
The honeysuckle band played all night long for only $90.
utter confusion followed.
It was an evening of splendid music and company.
Too bad the disco floor fell through at 23:00.
The local nurse Miss P.Neave was in attendance.

插入文本:
插入命令类似于附加命令,只是在指定行前面插入。和附加命令一样,它也只接受一个地址。
如在a t t e n d a n c e结尾的行前插入文本utter confusion followed

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CODE:

[sam@chenwy sam]$ sed "/company/i\Utter confusion followed." quote.txt


也可以指定行:

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CODE:

[sam@chenwy sam]$ cat insert.sed
#!/bin/sed -f
4 i\
Utter confusion followed.


执行结果

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CODE:

[sam@chenwy sam]$ chmod u+x insert.sed
[sam@chenwy sam]$ ./insert.sed quote.txt
The honeysuckle band played all night long for only $90.
It was an evening of splendid music and company.
Too bad the disco floor fell through at 23:00.
Utter confusion followed.
The local nurse Miss P.Neave was in attendance.


修改文本
修改命令将在匹配模式空间的指定行用新文本加以替代,格式如下:
将第一行The honeysuckle band played all night long for only $90替换为The office Di b b l e  band played well。首先要匹配第一行的任何部分,可使用模式‘ / H o n e y s u c k l e /’s e d脚本文件为c h a n g e . s e d。内容如下:

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CODE:

[sam@chenwy sam]$ cat change.sed
#!/bin/sed -f
3 c\
The office Dibble band played well.



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CODE:

[sam@chenwy sam]$ chmod u+x change.sed
[sam@chenwy sam]$ ./change.sed quote.txt
The honeysuckle band played all night long for only $90.
It was an evening of splendid music and company.
The office Dibble band played well.
The local nurse Miss P.Neave was in attendance.


或命令行:

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CODE:

[sam@chenwy sam]$ sed "/honeysuck/c\The Office Dibble band played well." quote.txt
The Office Dibble band played well.
It was an evening of splendid music and company.
Too bad the disco floor fell through at 23:00.
The local nurse Miss P.Neave was in attendance.


可以对同一个脚本中的相同文件进行修改、附加、插入三种动作匹配和混合操作。

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CODE:

[sam@chenwy sam]$ cat mix.sed
#!/bin/sed -f
1 c\
The Dibble band were grooving.

/evening/ i\
They played some great tunes.

3 a\
Where was the nurse to help?



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CODE:

[sam@chenwy sam]$ chmod u+x mix.sed
[sam@chenwy sam]$ ./mix.sed quote.txt
The Dibble band were grooving.
They played some great tunes.
It was an evening of splendid music and company.
Too bad the disco floor fell through at 23:00.
Where was the nurse to help?
The local nurse Miss P.Neave was in attendance.


删除文本
s e d
删除文本格式:

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CODE:

[ a d d r e s s [a d d r e s s ] ] d


删除第一行;1 d意为删除第一行。

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CODE:

[sam@chenwy sam]$ sed '1d' quote.txt
It was an evening of splendid music and company.
Too bad the disco floor fell through at 23:00.
The local nurse Miss P.Neave was in attendance.


删除第一到第三行:

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CODE:

[sam@chenwy sam]$ sed '1,3d' quote.txt
The local nurse Miss P.Neave was in attendance.


删除最后一行:

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CODE:

[sam@chenwy sam]$ sed '$d' quote.txt
The honeysuckle band played all night long for only $90.
It was an evening of splendid music and company.
Too bad the disco floor fell through at 23:00.


也可以使用正则表达式进行删除操作。下面的例子删除包含文本‘ N e a v e’的行。

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CODE:

[sam@chenwy sam]$ sed '/Neave/d' quote.txt
The honeysuckle band played all night long for only $90.
It was an evening of splendid music and company.
Too bad the disco floor fell through at 23:00.