sed的精华贴

最新推荐文章于 2025-04-25 17:17:40 发布

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最新推荐文章于 2025-04-25 17:17:40 发布

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分类专栏： Shell 文章标签： newline stream input 正则表达式 processing command

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测试：

以 Redhat6.0 为测试环境
事实上在solaris下的sed命令要比linux强，但因为没有测试
环境，我这里只给在linux下经过测试的用法。

★ 命令行参数简介
★ 首先假设我们有这样一个文本文件 sedtest.txt
★ 输出指定范围的行 p
★ 在每一行前面增加一个制表符(^I)
★ 在每一行后面增加--end
★ 显示指定模式匹配行的行号 [/pattern/]=
★ 在匹配行后面增加文本 [/pattern/]a/ 或者 [address]a/
★ 删除匹配行 [/pattern/]d 或者 [address1][,address2]d
★ 替换匹配行 [/pattern/]c/ 或者 [address1][,address2]c/
★ 在匹配行前面插入文本 [/pattern/]i/ 或者 [address]i/
★ 替换匹配串(注意不再是匹配行) [addr1][,addr2]s/old/new/g
★ 限定范围后的模式匹配
★ 指定替换每一行中匹配的第几次出现
★ &代表最后匹配
★ 利用sed修改PATH环境变量
★ 测试并提高sed命令运行效率
★ 指定输出文件 [address1][,address2]w outputfile
★ 指定输入文件 [address]r inputfile
★ 替换相应字符 [address1][,address2]y/old/new/
★ !号的使用
★ /c正则表达式c 的使用
★ sed命令中正则表达式的复杂性
★ 转换man手册成普通文本格式(新)
★ sed的man手册(用的就是上面的方法)
★ 命令行参数简介

sed
-e script 指定sed编辑命令
-f scriptfile 指定的文件中是sed编辑命令
-n 寂静模式，抑制来自sed命令执行过程中的冗余输出信息，比如只
显示那些被改变的行。

不明白？不要紧，把这些肮脏丢到一边，跟我往下走，不过下面的介绍里
不包括正则表达式的解释，如果你不明白，可能有点麻烦。

★ 首先假设我们有这样一个文本文件 sedtest.txt

cat > sedtest.txt
Sed is a stream editor
----------------------
A stream editor is used to perform basic text transformations on an nput stream
--------------------------------------------------------------------------------
While in some ways similar to an editor which permits scripted edits (such as ed
)
,
--------------------------------------------------------------------------------
sed works by making only one pass over the input(s), and is consequently more

-----------------------------------------------------------------------------

efficient. But it is sed's ability to filter text in a pipeline which particular
l
★ 输出指定范围的行 p other types of editors.

sed -e "1,4p" -n sedtest.txt
sed -e "/from/p" -n sedtest.txt
sed -e "1,/from/p" -n sedtest.txt

★ 在每一行前面增加一个制表符(^I)
sed "s/^/^I/g" sedtest.txt
注意^I的输入方法是ctrl-v ctrl-i
单个^表示行首

★ 在每一行后面增加--end

sed "s/$/--end/g" sedtest.txt
单个$表示行尾

★ 显示指定模式匹配行的行号 [/pattern/]=
sed -e '/is/=' sedtest.txt
1

Sed is a stream editor
----------------------

A stream editor is used to perform basic text transformations on an input stream

--------------------------------------------------------------------------------

While in some ways similar to an editor which permits scripted edits (such as ed

)

--------------------------------------------------------------------------------

sed works by making only one pass over the input(s), and is consequently more

-----------------------------------------------------------------------------

efficient. But it is sed's ability to filter text in a pipeline which particular

--------------------------------------------------------------------------------

意思是分析sedtest.txt，显示那些包含is串的匹配行的行号，注意11行中出现了is字符串这个输出是面向stdout的，如果不做重定向处理，则不影响原来的sedtest.txt

★ 在匹配行后面增加文本 [/pattern/]a/ 或者 [address]a/
^D

sed -f sedadd.script sedtest.txt
Sed is a stream editor
A stream editor is used to perform basic text transformations on an input stream
While in some ways similar to an editor which permits scripted edits (such as ed
)

--------------------------------------------------------------------------------

sed works by making only one pass over the input(s), and is consequently more

-----------------------------------------------------------------------------

efficient. But it is sed's ability to filter text in a pipeline which particular

--------------------------------------------------------------------------------

[scz@ /home/scz/src]> sed -e "a//

+++++++++

---------------------------------------------

找到包含from字符串的行，在该行的下一行增加+++++++++。

这个输出是面向stdout的，如果不做重定向处理，则不影响原来的sedtest.txt

很多人想在命令行上直接完成这个操作而不是多一个sedadd.script，不幸的是，这需要用

续行符/，

[scz@ /home/scz/src]> sed -e "/from/a//

> +++++++++" sedtest.txt

[scz@ /home/scz/src]> sed -e "a//

> +++++++++" sedtest.txt

上面这条命令将在所有行后增加一个新行+++++++++

[scz@ /home/scz/src]> sed -e "1 a//

> +++++++++" sedtest.txt

把下面这两行copy/paste到一个shell命令行上，效果一样

+++++++++" sedtest.txt

[address]a/ 只接受一个地址指定

对于a命令，不支持单引号，只能用双引号，而对于d命令等其他命令，同时

★ 删除匹配行 [/pattern/]d 或者 [address1][,address2]d

sed -e '/---------------------------------------------/d' sedtest.txt

Sed is a stream editor

A stream editor is used to perform basic text transformations on an input stream

While in some ways similar to an editor which permits scripted edits (such as ed

)

sed works by making only one pass over the input(s), and is consequently more

efficient. But it is sed's ability to filter text in a pipeline which particular

sed -e '6,10d' sedtest.txt

删除6-10行的内容，包括6和10

sed -e "2d" sedtest.txt

删除第2行的内容

sed "1,/^$/d" sedtest.txt

删除从第一行到第一个空行之间的所有内容

注意这个命令很容易带来意外的结果，当sedtest.txt中从第一行开始并没有空行，则sed

sed "1,/from/d" sedtest.txt

删除从第一行到第一个包含from字符串的行之间的所有内容，包括第一个包含

from字符串的行。

★ 替换匹配行 [/pattern/]c/ 或者 [address1][,address2]c/

sed -e "/is/c//

**********" sedtest.txt

寻找所有包含is字符串的匹配行，替换成**********

**********

----------------------

**********

--------------------------------------------------------------------------------

While in some ways similar to an editor which permits scripted edits (such as ed

)

--------------------------------------------------------------------------------

**********

-----------------------------------------------------------------------------

**********

--------------------------------------------------------------------------------

sed -e "1,11c//

**********" sedtest.txt----------------------

在1-12行内搜索所有from字符串，分别替换成****字符串

★ 限定范围后的模式匹配

sed "/But/s/is/are/g" sedtest.txt

对那些包含But字符串的行，把is替换成are

sed "/is/s/t/T/" sedtest.txt

对那些包含is字符串的行，把每行第一个出现的t替换成T

sed "/While/,/from/p" sedtest.txt -n

输出在这两个模式匹配行之间的所有内容

★ 指定替换每一行中匹配的第几次出现

sed "s/is/are/5" sedtest.txt

把每行的is字符串的第5次出现替换成are

★ &代表最后匹配

sed "s/^$/(&)/" sedtest.txt

给所有空行增加一对()

sed "s/is/(&)/g" sedtest.txt

给所有is字符串外增加()

sed "s/.*/(&)/" sedtest.txt

给所有行增加一对()

sed "/is/s/.*/(&)/" sedtest.txt

给所有包含is字符串的行增加一对()

★ 利用sed修改PATH环境变量

先查看PATH环境变量

[scz@ /home/scz/src]> echo $PATH

/usr/bin:/usr/bin:/bin:/usr/local/bin:/sbin:/usr/sbin:/usr/X11R6/bin:.

去掉尾部的{ :/usr/X11R6/bin:. }

[scz@ /home/scz/src]> echo $PATH | sed "s/^/(.*/)://usr[/]X11R6//bin:[.]$//1/"

/usr/bin:/usr/bin:/bin:/usr/local/bin:/sbin:/usr/sbin

去掉中间的{ :/bin: }

[scz@ /home/scz/src]> echo $PATH | sed "s/^/(.*/)://bin:/(.*/)$//1/2/"

/usr/bin:/usr/bin/usr/local/bin:/sbin:/usr/sbin:/usr/X11R6/bin:.

[/]表示/失去特殊意义

//同样表示/失去意义

/1表示子匹配的第一次出现

/2表示子匹配的第二次出现

/(.*/)表示子匹配

去掉尾部的:，然后增加新的路径

PATH=`echo $PATH | sed 's//(.*/):$//1/'`:$HOME/src

注意反引号`和单引号'的区别。

★ 测试并提高sed命令运行效率

time sed -n "1,12p" webkeeper.db > /dev/null

time sed 12q webkeeper.db > /dev/null

可以看出后者比前者效率高。

[address]q 当碰上指定行时退出sed执行

★ 指定输出文件 [address1][,address2]w outputfile

sed "1,10w sed.out" sedtest.txt -n

将sedtest.txt中1-10行的内容写到sed.out文件中。

★ 指定输入文件 [address]r inputfile

sed "1r sedappend.txt" sedtest.txt

将sedappend.txt中的内容附加到sedtest.txt文件的第一行之后

★ 替换相应字符 [address1][,address2]y/old/new/

sed "y/abcdef/ABCDEF/" sedtest.txt

将sedtest.txt中所有的abcdef小写字母替换成ABCDEF大写字母。

★ !号的使用

sed -e '3,7!d' sedtest.txt

删除3-7行之外的所有行

sed -e '1,/from/!d' sedtest.txt

找到包含from字符串的行，删除其后的所有行

★ /c正则表达式c 的使用

sed -e "/:from:d" sedtest.txt

等价于 sed -e "/from/d" sedtest.txt

★ sed命令中正则表达式的复杂性

cat > sedtest.txt

^//[}]{.*}[/(]$/)

如何才能把该行替换成

/(]$/)//[}]{.*}^[

★ 转换man手册成普通文本格式(新)

man sed | col -b > sed.txt

sed -e "s/^H//g" -e "/^$/d" -e "s/^^I/ /g" -e "s/^I/ /g" sed.txt > sedman

txt

删除所有退格键、空行，把行首的制表符替换成8个空格，其余制表符替换成一个空格。

★ sed的man手册(用的就是上面的方法)

NAME

sed - a Stream EDitor

SYNOPSIS

sed [-n] [-V] [--quiet] [--silent] [--version] [--help]

[-e script] [--expression=script]

[-f script-file] [--file=script-file]

[script-if-no-other-script]

[file...]

DESCRIPTION

Sed is a stream editor. A stream editor is used to per-

form basic text transformations on an input stream (a file

or input from a pipeline). While in some ways similar to

an editor which permits scripted edits (such as ed), sed

works by making only one pass over the input(s), and is

consequently more efficient. But it is sed's ability to

filter text in a pipeline which particularly distinguishes

it from other types of editors.

OPTIONS

Sed may be invoked with the following command-line

options:

-V

--version

Print out the version of sed that is being run and

a copyright notice, then exit.

-h

--help Print a usage message briefly summarizing these

command-line options and the bug-reporting address,

then exit.

-n

--quiet

--silent

By default, sed will print out the pattern space at

the end of each cycle through the script. These

options disable this automatic printing, and sed

will only produce output when explicitly told to

via the p command.

-e script

--expression=script

Add the commands in script to the set of commands

to be run while processing the input.

-f script-file

--file=script-file

Add the commands contained in the file script-file

to the set of commands to be run while processing

the input.

If no -e,-f,--expression, or --file options are given on

the command-line, then the first non-option argument on

the command line is taken to be the script to be executed.

If any command-line parameters remain after processing the

above, these parameters are interpreted as the names of

input files to be processed. A file name of - refers to

the standard input stream. The standard input will pro-

cessed if no file names are specified.

Command Synopsis

This is just a brief synopsis of sed commands to serve as

a reminder to those who already know sed; other documenta-

tion (such as the texinfo document) must be consulted for

fuller descriptions.

Zero-address ``commands''

: label

Label for b and t commands.

#comment

The comment extends until the next newline (or the

end of a -e script fragment).

} The closing bracket of a { } block.

Zero- or One- address commands

= Print the current line number.

a /

text Append text, which has each embedded newline pre-

ceeded by a backslash.

i /

text Insert text, which has each embedded newline pre-

ceeded by a backslash.

q Immediately quit the sed script without processing

any more input, except that if auto-print is not

diabled the current pattern space will be printed.

r filename

Append text read from filename.

Commands which accept address ranges

{ Begin a block of commands (end with a }).

b label

Branch to label; if label is omitted, branch to end

of script.

t label

If a s/// has done a successful substitution since

the last input line was read and since the last t

command, then branch to label; if label is omitted,

branch to end of script.

c /

text Replace the selected lines with text, which has

each embedded newline preceeded by a backslash.

d Delete pattern space. Start next cycle.

D Delete up to the first embedded newline in the pat-

tern space. Start next cycle, but skip reading

from the input if there is still data in the pat-

tern space.

h H Copy/append pattern space to hold space.

g G Copy/append hold space to pattern space.

x Exchange the contents of the hold and pattern

spaces.

l List out the current line in a ``visually unambigu-

ous'' form.

n N Read/append the next line of input into the pattern

space.

p Print the current pattern space.

P Print up to the first embedded newline of the cur-

rent pattern space.

s/regexp/replacement/

Attempt to match regexp against the pattern space.

If successful, replace that portion matched with

replacement. The replacement may contain the spe-

cial character & to refer to that portion of the

pattern space which matched, and the special

escapes /1 through /9 to refer to the corresponding

matching sub-expressions in the regexp.

w filename Write the current pattern space to file-

name.

y/source/dest/

Transliterate the characters in the pattern space

which appear in source to the corresponding charac-

ter in dest.

Addresses

Sed commands can be given with no addresses, in which case

the command will be executed for all input lines; with one

address, in which case the command will only be executed

for input lines which match that address; or with two

addresses, in which case the command will be executed for

all input lines which match the inclusive range of lines

starting from the first address and continuing to the sec-

ond address. Three things to note about address ranges:

the syntax is addr1,addr2 (i.e., the addresses are sepa-

rated by a comma); the line which addr1 matched will

always be accepted, even if addr2 selects an earlier line;

and if addr2 is a regexp, it will not be tested against

the line that addr1 matched.

After the address (or address-range), and before the com-

mand, a ! may be inserted, which specifies that the com-

mand shall only be executed if the address (or address-

range) does not match.

The following address types are supported:

number Match only the specified line number.

first~step

Match every step'th line starting with line first.

For example, ``sed -n 1~2p'' will print all the

odd-numbered lines in the input stream, and the

address 2~5 will match every fifth line, starting

with the second. (This is a GNU extension.)

$ Match the last line.

/regexp/

Match lines matching the regular expression regexp.

/cregexpc

Match lines matching the regular expression regexp.

The c may be any character.

Regular expressions

POSIX.2 BREs should be supported, but they aren't com-

pletely yet. The /n sequence in a regular expression

matches the newline character. There are also some GNU

extensions. [XXX FIXME: more needs to be said. At the

very least, a reference to another document which

describes what is supported should be given.]

Miscellaneous notes

This version of sed supports a /<newline> sequence in all

regular expressions, the replacement part of a substitute

(s) command, and in the source and dest parts of a

transliterate (y) command. The / is stripped, and the

newline is kept.