sed 是一种在线编辑器，它一次处理一行内容。处理时，把当前处理的行存储在临时缓冲区中，称为“模式空间”（pattern space），接着用sed命令处理缓冲区中的内容，处理完成后，把缓冲区的内容送往屏幕。接着处理下一行，这样不断重复，直到文件末尾。文件内容并没有 改变，除非你使用重定向存储输出。Sed主要用来自动编辑一个或多个文件；简化对文件的反复操作；编写转换程序等。
[root@localhost sed]# cat sed_append.txt this is line a this is line b
this is line c this is line d # helloworld_1 # helloworld_2 # helloworld_3 [root@localhost sed]# sed '/^$/d' sed_append.txt this is line a this is line b this is line c this is line d # helloworld_1 # helloworld_2 # helloworld_3 [root@localhost sed]# cat sed_append.txt this is line a this is line b
this is line c this is line d # helloworld_1 # helloworld_2 # helloworld_3 [root@localhost sed]#
[root@localhost sed]# cat sed_append.txt this is line a this is line b
this is line c this is line d # helloworld_1 # helloworld_2 # helloworld_3 [root@localhost sed]# sed -i '/^$/d' sed_append.txt [root@localhost sed]# cat sed_append.txt this is line a this is line b this is line c this is line d # helloworld_1 # helloworld_2 # helloworld_3 [root@localhost sed]#
[root@localhost sed]# cat sed_append.txt this is line a this is line b this is line c this is line d # helloworld_1 # helloworld_2 # helloworld_3 [root@localhost sed]# sed '/^#/,$d' sed_append.txt this is line a this is line b this is line c this is line d [root@localhost sed]# sed -i '/^#/,$d' sed_append.txt [root@localhost sed]# cat sed_append.txt this is line a this is line b this is line c this is line d [root@localhost sed]#
[root@localhost sed]# cat sed_append.txt this is line a this is line b this is line c this is line d # helloworld_1 # helloworld_2 # helloworld_3 [root@localhost sed]# sed 's/^/#/g' sed_append.txt #this is line a #this is line b #this is line c #this is line d ## helloworld_1 ## helloworld_2 ## helloworld_3 [root@localhost sed]#
在行尾添加内容
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[root@localhost sed]# cat sed_append.txt this is line a this is line b this is line c this is line d # helloworld_1 # helloworld_2 # helloworld_3 [root@localhost sed]# sed 's/$/。/g' sed_append.txt this is line a。 this is line b。 this is line c。 this is line d。 # helloworld_1。 # helloworld_2。 # helloworld_3。 [root@localhost sed]#
[root@localhost sed]# cat -n SedTest.java 1 public class SedTest{ 2 public static void main(String[] args){ 3 System.out.println("HelloWorld!"); 4 System.out.println("sed命令示例"); 5 System.out.println("sed替换示例"); 6 for(int i=0;i<5;i++){ 7 System.out.println("sed_sed_sed_sed"+i); 8 } 9 } 10 } [root@localhost sed]# sed '1,2d' SedTest.java System.out.println("HelloWorld!"); System.out.println("sed命令示例"); System.out.println("sed替换示例"); for(int i=0;i<5;i++){ System.out.println("sed_sed_sed_sed"+i); } } } [root@localhost sed]# sed '1,2s/\t/----/g' SedTest.java public class SedTest{ ----public static void main(String[] args){ System.out.println("HelloWorld!"); System.out.println("sed命令示例"); System.out.println("sed替换示例"); for(int i=0;i<5;i++){ System.out.println("sed_sed_sed_sed"+i); } } } [root@localhost sed]#
删除空行
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sed '/^$/d' a.txt #删除所有空行
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[root@localhost sed]# cat sed_append.txt this is line a this is line b
this is line c this is line d [root@localhost sed]# sed '/^$/d' sed_append.txt this is line a this is line b this is line c this is line d [root@localhost sed]#
删除#开头的行，到最后一行：
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[root@localhost sed]# cat sed_append.txt this is line a this is line b
this is line c this is line d # helloworld_1 # helloworld_2 # helloworld_3 [root@localhost sed]# sed '/^#/,$d' sed_append.txt this is line a this is line b
this is line c this is line d [root@localhost sed]#
sed脚本命令a：在指定行后追加新行
在第N行之后附加新的内容
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sed '行号a 附加的内容'
在某行之后追加一行
例如，在第2行只有追加一行字符串this is the newly inserted line：
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[root@localhost sed]# cat -n sed_append.txt 1 this is line a 2 this is line b 3 this is line c 4 this is line d [root@localhost sed]# sed '2a this is the newly inserted line' sed_append.txt |cat -n 1 this is line a 2 this is line b 3 this is the newly inserted line 4 this is line c 5 this is line d [root@localhost sed]#
在某行之后追加多行
使用折行符号
使用在单引号中使用折行符\可以追加多行到指定行的后面：
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[root@localhost sed]# cat -n sed_append.txt 1 this is line a 2 this is line b 3 this is line c 4 this is line d [root@localhost sed]# sed '2a this is the newly inserted line 1\ this is the newly inserted line 2' sed_append.txt |cat -n 1 this is line a 2 this is line b 3 this is the newly inserted line 1 4 this is the newly inserted line 2 5 this is line c 6 this is line d [root@localhost sed]#
使用换行符\n
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[root@localhost sed]# cat -n sed_append.txt 1 this is line a 2 this is line b 3 this is line c 4 this is line d 5 helloworld1 6 helloworld2 [root@localhost sed]# sed '1i this is the newly inserted line 1\nthis is the newly inserted line 2' sed_append.txt |cat -n 1 this is the newly inserted line 1 2 this is the newly inserted line 2 3 this is line a 4 this is line b 5 this is line c 6 this is line d 7 helloworld1 8 helloworld2 [root@localhost sed]#
sed脚本命令i：在指定行之前插入新行
在第N行之前插入一行
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[root@localhost sed]# cat -n sed_append.txt 1 this is line a 2 this is line b 3 this is line c 4 this is line d [root@localhost sed]# sed '2i this is the newly inserted line' sed_append.txt |cat -n 1 this is line a 2 this is the newly inserted line 3 this is line b 4 this is line c 5 this is line d [root@localhost sed]#
在第N行之前插入多行
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[root@localhost sed]# cat -n sed_append.txt 1 this is line a 2 this is line b 3 this is line c 4 this is line d [root@localhost sed]# sed '2i this is the newly inserted line 1\ this is the newly inserted line 2' sed_append.txt |cat -n 1 this is line a 2 this is the newly inserted line 1 3 this is the newly inserted line 2 4 this is line b 5 this is line c 6 this is line d [root@localhost sed]#
sed脚本命令c：替换整行
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[address]c\用于替换的新文本
替换第2行的内容
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[root@localhost sed]# cat -n sed_append.txt 1 this is line a 2 this is line b 3 this is line c 4 this is line d [root@localhost sed]# sed '2c this is the line after replacement' sed_append.txt |cat -n 1 this is line a 2 this is the line after replacement 3 this is line c 4 this is line d [root@localhost sed]#
[root@localhost sed]# cat sed_append.txt this is line a this is line b this is line c this is line d [root@localhost sed]# sed 'y/abcd/1234/' sed_append.txt this is line 1 this is line 2 this is line 3 this is line 4 [root@localhost sed]# sed '1,2y/abcd/1234/' sed_append.txt this is line 1 this is line 2 this is line c this is line d [root@localhost sed]#
[root@localhost sed]# cat sed_append.txt
this is line a
this is line b
this is line c
this is line d
[root@localhost sed]# sed '1,2y/abcde/12345/' sed_append.txt
this is lin5 1
this is lin5 2
this is line c
this is line d
[root@localhost sed]#
大小写转换
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[root@localhost sed]# cat sed_append.txt this is line a this is line b this is line c this is line d [root@localhost sed]# sed '1,2y/abcdefghijklmnopqrstuvwxyz/ABCDEFGHIJKLMNOPQRSTUVWXYZ/' sed_append.txt THIS IS LINE A THIS IS LINE B this is line c this is line d [root@localhost sed]#
sed脚本命令p：打印某行
sed 默认会打印出被处理的输入内容，这些内容跟原始输入内容不一定完全一样，sed 的一些命令可以修改或删除输入内容，再把新的内容打印出来。 打印的输出结果并不是只对应匹配特定模式的行。 那些没有被处理的行，会原样打印。 如果只想打印匹配特定模式的行，要用 -n 选项和 p 命令。
注意：-n 选项并不表示打印匹配特定模式且被处理的行。 例如，使用 -n 选项和 d 命令不会看到任何打印，并不会打印出被删除的行。
sed -n∶使用安静(silent)模式。在一般 sed 的用法中，所有来自STDIN的资料一般都会被列出到萤幕上。但如果加上 -n 参数后，则只有经过sed 特殊处理的那一行(或者动作)才会被列出来。
sed ‘[address]p’ 输出匹配的行
p命令表示搜索符号条件的行，并输出该行的内容。
[root@localhost sed]# cat sed_append.txt
this is line a
this is line b
this is line c
this is line d
# helloworld_1
# helloworld_2
# helloworld_3
[root@localhost sed]# sed '/^#/p' sed_append.txt
this is line a
this is line b
this is line c
this is line d
# helloworld_1
# helloworld_1
# helloworld_2
# helloworld_2
# helloworld_3
# helloworld_3
[root@localhost sed]#
[root@localhost sed]# cat sed_append.txt
this is line a
this is line b
this is line c
this is line d
# helloworld_1
# helloworld_2
# helloworld_3
[root@localhost sed]# sed -n '/^#/p' sed_append.txt
# helloworld_1
# helloworld_2
# helloworld_3
[root@localhost sed]#
通常 p 会与参数 sed -n 一起运作。此命令的基本格式为：
sed -n ‘[address]p’
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sed -n '[address]p'
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sed -n '1p' filename #显示第一行 sed -n '$p' filename #显示最后一行 sed -n '1,2p' filename #显示第一行到第二行 sed -n '2,$p' filename #显示第二行到最后一行
p 命令常见的用法是打印包含匹配文本模式的行，例如：
打印第一行
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[root@localhost sed]# cat sed_append.txt this is line a this is line b this is line c this is line d [root@localhost sed]# sed -n '1p' sed_append.txt this is line a [root@localhost sed]#
打印最后一行
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[root@localhost sed]# cat sed_append.txt this is line a this is line b this is line c this is line d helloworld1 helloworld2 [root@localhost sed]# sed -n '$p' sed_append.txt helloworld2 [root@localhost sed]#
打印第1行到第2行
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[root@localhost sed]# sed -n '1,2p' sed_append.txt this is line a this is line b [root@localhost sed]#
打印第2行到最后一行
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[root@localhost sed]# sed -n '2,$p' sed_append.txt this is line b this is line c this is line d helloworld1 helloworld2 [root@localhost sed]#
打印包含指定关键字的行
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[root@localhost sed]# cat sed_append.txt this is line a this is line b this is line c this is line d helloworld1 helloworld2 [root@localhost sed]# sed -n '/helloworld/p' sed_append.txt helloworld1 helloworld2
打印匹配正则表达式的行
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[root@localhost sed]# cat sed_append.txt this is line a this is line b this is line c this is line d helloworld1 helloworld2 [root@localhost sed]# sed -n '/world[0-9]/p' sed_append.txt helloworld1 helloworld2 [root@localhost sed]#
sed -n选项p命令：只打印包含匹配模式的行
可以看到，用 -n 选项和 p 命令配合使用，可以只打印匹配的行。
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[root@localhost sed]# cat sed_append.txt this is line a this is line b this is line c this is line d [root@localhost sed]# sed -n '2p' sed_append.txt this is line b [root@localhost sed]# sed -n '/b/p' sed_append.txt this is line b [root@localhost sed]# sed -n '/line/p' sed_append.txt this is line a this is line b this is line c this is line d [root@localhost sed]#
[root@localhost sed]# cat sed_append.txt this is line a this is line b this is line c this is line d [root@localhost sed]# sed -n '/b/{ > p; > s/line/row/p > }' sed_append.txt this is line b this is row b [root@localhost sed]#
sed 命令会查找包含小写字母b的行，然后执行两条命令。 首先，脚本用 p 命令来打印出原始行； 然后它用s命令替换文本，并用 p 标记打印出替换结果。 这样可以输出当前要处理的文本，以及替换之后的文本，以便于对比替换的结果是否达到要求
多个脚本命令写在一行
可以吧多个命令写在一行之中，命令之间用英文的分号;分隔开即可：
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sed '[address]{命令1;命令2;...命令n}'
[root@localhost sed]# cat sed_append.txt
this is line a
this is line b
this is line c
this is line d
# helloworld_1
# helloworld_2
# helloworld_3
[root@localhost sed]# sed -n '/^#/,${p;s/helloworld/HELLOWORLD/pg}' sed_append.txt
# helloworld_1
# HELLOWORLD_1
# helloworld_2
# HELLOWORLD_2
# helloworld_3
# HELLOWORLD_3
[root@localhost sed]#
[root@localhost sed]# cat sed_append.txt
this is line a
this is line b
this is line c
this is line d
# helloworld_1
# helloworld_2
# helloworld_3
[root@localhost sed]# sed -n '/\<hello/p' sed_append.txt
# helloworld_1
# helloworld_2
# helloworld_3
[root@localhost sed]#
打印有line为词尾的单词的行
[root@localhost sed]# cat sed_append.txt
this is line a
this is line b
this is line c
this is line d
# helloworld_1
# helloworld_2
# helloworld_3
[root@localhost sed]# sed -n '/line\>/p' sed_append.txt
this is line a
this is line b
this is line c
this is line d
[root@localhost sed]#
sed脚本命令w file：输出模式空间中的内容到文件
w命令用来将文本中指定行的内容写入文件中，此命令的基本格式如下：
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sed '[address]w filename'
这里的 filename 表示文件名，可以使用相对路径或绝对路径，但不管是哪种，运行 sed 命令的用户都必须有文件的写权限。 下面的例子是将数据流中的前两行打印到一个文本文件中：
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[root@localhost sed]# cat sed_append.txt this is line a this is line b this is line c this is line d [root@localhost sed]# sed '1,2 w sed_w_out.txt' sed_append.txt this is line a this is line b this is line c this is line d [root@localhost sed]# cat sed_w_out.txt this is line a this is line b [root@localhost sed]#
sed脚本命令r：插入独立文件的内容到当前数据流的指定位置
r 命令用于将一个独立文件的数据插入到当前数据流的指定位置，该命令的基本格式为：
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sed "[address]r filename"
sed命令会将filename文件中的内容插入到address指定的行的后面。
在文件的某行后插入另一个文件的内容
例如，将sed_2.txt文件中的内容，插入到sed_append.txt文件中的第二行后面：
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[root@localhost sed]# cat sed_append.txt this is line a this is line b this is line c this is line d [root@localhost sed]# cat sed_2.txt HelloWorld [root@localhost sed]# sed "2r sed_2.txt" sed_append.txt this is line a this is line b HelloWorld this is line c this is line d [root@localhost sed]#
在文件的末尾插入另一个文件的内容
如果你想将指定文件中的数据插入到数据流的末尾，可以使用地址符$，例如：
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[root@localhost sed]# cat sed_append.txt this is line a this is line b this is line c this is line d [root@localhost sed]# cat sed_2.txt HelloWorld [root@localhost sed]# sed '$r sed_2.txt' sed_append.txt this is line a this is line b this is line c this is line d HelloWorld
[root@localhost sed]# sed "$r sed_2.txt" sed_append.txt sed：-e 表达式 #1，字符 10：未终止的“s”命令 [root@localhost sed]# sed "\$r sed_2.txt" sed_append.txt this is line a this is line b this is line c this is line d HelloWorld [root@localhost sed]#
sed脚本命令q：匹配第一次后就退出sed程序
q命令的作用是使sed命令在第一次匹配任务结束后，退出 sed 程序，不再进行对后续数据的处理。
sed匹配后退出
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[root@localhost sed]# cat sed_append.txt this is line a this is line b this is line c this is line d [root@localhost sed]# sed '2q' sed_append.txt this is line a this is line b [root@localhost sed]#
可以看到，sed 命令在打印输出第 2 行之后，就停止了，是 q 命令造成的，再比如：
sed查找替换第一次模式匹配后退出
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[root@localhost sed]# cat sed_append.txt this is line a this is line b this is line c this is line d [root@localhost sed]# sed '/b/{ s/b/B/;q; }' sed_append.txt this is line a this is line B [root@localhost sed]#
[root@localhost sed]# cat sed_append.txt this is line a this is line b this is line c this is line d [root@localhost sed]# sed '2s/s/_/g' sed_append.txt this is line a thi_ i_ line b this is line c this is line d [root@localhost sed]#
可以看到，sed 只修改地址指定的第二行的文本。下面的例子中使用了行地址区间：
使用区间指定行地址
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[root@localhost sed]# cat sed_append.txt this is line a this is line b this is line c this is line d [root@localhost sed]# sed '2,3s/s/_/g' sed_append.txt this is line a thi_ i_ line b thi_ i_ line c this is line d [root@localhost sed]#
特殊的行结束符$
在此基础上，如果想将命令作用到文本中从某行开始的所有行，可以用特殊地址——美元符（$）：
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[root@localhost sed]# cat sed_append.txt this is line a this is line b this is line c this is line d [root@localhost sed]# sed '2,$s/s/_/g' sed_append.txt this is line a thi_ i_ line b thi_ i_ line c thi_ i_ line d [root@localhost sed]#
用文本模式指定行区间
sed 允许指定文本模式来过滤出命令要作用的行，格式如下：
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/pattern/command
注意，必须用正斜线将要指定的pattern封起来，sed会将该命令作用到包含指定文本模式的行上。
固定文本模式：字符串形式的文本模式
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[root@localhost sed]# cat sed_append.txt this is line a this is line b this is line c this is line d helloworld1 helloworld2 [root@localhost sed]# cat sed_append.txt |grep 'helloworld' helloworld1 helloworld2 [root@localhost sed]# sed '/helloworld/s/helloworld/HELLOWORLD/g' sed_append.txt this is line a this is line b this is line c this is line d HELLOWORLD1 HELLOWORLD2 [root@localhost sed]#
[root@localhost sed]# cat sed_append.txt this is line a this is line b this is line c this is line d helloworld1 helloworld2 [root@localhost sed]# sed '/world[0-9]/s/world/WORLD/g' sed_append.txt this is line a this is line b this is line c this is line d helloWORLD1 helloWORLD2 [root@localhost sed]#
[root@localhost ~]# sed --help 用法: sed [选项]... {脚本(如果没有其他脚本)} [输入文件]...
-n, --quiet, --silent 取消自动打印模式空间 -e 脚本, --expression=脚本 添加“脚本”到程序的运行列表 -f 脚本文件, --file=脚本文件 添加“脚本文件”到程序的运行列表 --follow-symlinks 直接修改文件时跟随软链接 -i[SUFFIX], --in-place[=SUFFIX] edit files in place (makes backup if SUFFIX supplied) -c, --copy use copy instead of rename when shuffling files in -i mode -b, --binary does nothing; for compatibility with WIN32/CYGWIN/MSDOS/EMX ( open files in binary mode (CR+LFs are not treated specially)) -l N, --line-length=N 指定“l”命令的换行期望长度 --posix 关闭所有 GNU 扩展 -r, --regexp-extended 在脚本中使用扩展正则表达式 -s, --separate 将输入文件视为各个独立的文件而不是一个长的连续输入 -u, --unbuffered 从输入文件读取最少的数据，更频繁的刷新输出 -z, --null-data separate lines by NUL characters --help display this help and exit --version output version information and exit
如果没有 -e, --expression, -f 或 --file 选项，那么第一个非选项参数被视为 sed脚本。其他非选项参数被视为输入文件，如果没有输入文件，那么程序将从标准 输入读取数据。 GNU sed home page: <http://www.gnu.org/software/sed/>. General help using GNU software: <http://www.gnu.org/gethelp/>. E-mail bug reports to: <bug-sed@gnu.org>. Be sure to include the word ``sed'' somewhere in the ``Subject:'' field. [root@localhost ~]#
NAME sed - stream editor for filtering and transforming text
SYNOPSIS sed [OPTION]... {script-only-if-no-other-script} [input-file]...
DESCRIPTION Sed is a stream editor. A stream editor is used to perform 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 distin‐ guishes it from other types of editors.
-n, --quiet, --silent
suppress automatic printing of pattern space
-e script, --expression=script
add the script to the commands to be executed
-f script-file, --file=script-file
add the contents of script-file to the commands to be executed
--follow-symlinks
follow symlinks when processing in place
-i[SUFFIX], --in-place[=SUFFIX]
edit files in place (makes backup if SUFFIX supplied)
-c, --copy
use copy instead of rename when shuffling files in -i mode
-b, --binary
does nothing; for compatibility with WIN32/CYGWIN/MSDOS/EMX ( open files in binary mode (CR+LFs are not treated specially))
-l N, --line-length=N
specify the desired line-wrap length for the `l' command
--posix
disable all GNU extensions.
-r, --regexp-extended
use extended regular expressions in the script.
-s, --separate
consider files as separate rather than as a single continuous long stream.
-u, --unbuffered
load minimal amounts of data from the input files and flush the output buffers more often
-z, --null-data
separate lines by NUL characters
--help
display this help and exit
--version
output version information and exit
If no -e, --expression, -f, or --file option is given, then the first non-option argument is taken as the sed script to interpret. All remaining arguments are names of input files; if no input files are specified, then the standard input is read.
GNU sed home page: <http://www.gnu.org/software/sed/>. General help using GNU software: <http://www.gnu.org/gethelp/>. E-mail bug reports to: <bug-sed@gnu.org>. Be sure to include the word ``sed'' somewhere in the ``Subject:'' field.
COMMAND SYNOPSIS This is just a brief synopsis of sed commands to serve as a reminder to those who already know sed; other documentation (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 preceded by a backslash.
i \
text Insert text, which has each embedded newline preceded by a backslash.
q [exit-code] Immediately quit the sed script without processing any more input, except that if auto-print is not disabled the current pat‐ tern space will be printed. The exit code argument is a GNU extension.
Q [exit-code] Immediately quit the sed script without processing any more input. This is a GNU extension.
r filename Append text read from filename.
R filename Append a line read from filename. Each invocation of the command reads a line from the file. This is a GNU extension.
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.
c \
text Replace the selected lines with text, which has each embedded newline preceded by a backslash.
d Delete pattern space. Start next cycle.
D If pattern space contains no newline, start a normal new cycle as if the d command was issued. Otherwise, delete text in the pattern space up to the first newline, and restart cycle with the resultant pattern space, without reading a new line of input.
h H Copy/append pattern space to hold space.
g G Copy/append hold space to pattern space.
l List out the current line in a ``visually unambiguous'' form.
l width List out the current line in a ``visually unambiguous'' form, breaking it at width characters. This is a GNU extension.
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 current pattern space.
s/regexp/replacement/ Attempt to match regexp against the pattern space. If successful, replace that portion matched with replacement. The replace‐ ment may contain the special 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.
t label If a s/// has done a successful substitution since the last input line was read and since the last t or T command, then branch to label; if label is omitted, branch to end of script.
T label If no s/// has done a successful substitution since the last input line was read and since the last t or T command, then branch to label; if label is omitted, branch to end of script. This is a GNU extension.
w filename Write the current pattern space to filename.
W filename Write the first line of the current pattern space to filename. This is a GNU extension.
x Exchange the contents of the hold and pattern spaces.
y/source/dest/ Transliterate the characters in the pattern space which appear in source to the corresponding character 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 com‐ mand will be executed for all input lines which match the inclusive range of lines starting from the first address and continuing to the second address. Three things to note about address ranges: the syntax is addr1,addr2 (i.e., the addresses are separated 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 command, a ! may be inserted, which specifies that the command 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 (which increments cumulatively across files, unless the -s option is specified on the com‐ mand line).
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. first can be zero; in this case, sed operates as if it were equal to step. (This is an 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.
GNU sed also supports some special 2-address forms:
0,addr2 Start out in "matched first address" state, until addr2 is found. This is similar to 1,addr2, except that if addr2 matches the very first line of input the 0,addr2 form will be at the end of its range, whereas the 1,addr2 form will still be at the begin‐ ning of its range. This works only when addr2 is a regular expression.
addr1,+N Will match addr1 and the N lines following addr1.
addr1,~N Will match addr1 and the lines following addr1 until the next line whose input line number is a multiple of N.
REGULAR EXPRESSIONS POSIX.2 BREs should be supported, but they aren't completely because of performance problems. The \n sequence in a regular expression matches the newline character, and similarly for \a, \t, and other sequences.
BUGS E-mail bug reports to bug-sed@gnu.org. Also, please include the output of ``sed --version'' in the body of your report if at all pos‐ sible.
AUTHOR Written by Jay Fenlason, Tom Lord, Ken Pizzini, and Paolo Bonzini. GNU sed home page: <http://www.gnu.org/software/sed/>. General help using GNU software: <http://www.gnu.org/gethelp/>. E-mail bug reports to: <bug-sed@gnu.org>. Be sure to include the word ``sed'' somewhere in the ``Subject:'' field.
SEE ALSO awk(1), ed(1), grep(1), tr(1), perlre(1), sed.info, any of various books on sed, the sed FAQ (http://sed.sf.net/grabbag/tutorials/sed‐ faq.txt), http://sed.sf.net/grabbag/.
The full documentation for sed is maintained as a Texinfo manual. If the info and sed programs are properly installed at your site, the command
info sed
should give you access to the complete manual.
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