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1 sed命令 帮助
Usage: sed [OPTION]... {script-only-if-no-other-script} [input-file]... -n, --quiet, --silent ###安静模式，只显示被sed处理过的行 suppress automatic printing of pattern space -e script, --expression=script ###默认选项，不用写，在命令行操作 add the script to the commands to be executed -f script-file, --file=script-file ### 将sed操作写在一个文件里 add the contents of script-file to the commands to be executed --follow-symlinks follow symlinks when processing in place; hard links will still be broken. -i[SUFFIX], --in-place[=SUFFIX] ### 插入当前行的上一行 edit files in place (makes backup if extension supplied). The default operation mode is to break symbolic and hard links. This can be changed with --follow-symlinks and --copy. -c, --copy use copy instead of rename when shuffling files in -i mode. While this will avoid breaking links (symbolic or hard), the resulting editing operation is not atomic. This is rarely the desired mode; --follow-symlinks is usually enough, and it is both faster and more secure. -l N, --line-length=N specify the desired line-wrap length for the `l‘ command --posix disable all GNU extensions. -r, --regexp-extended ###支持扩展正则表达式 use extended regular expressions in the script. -s, --separate ###表示搜索 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 --help display this help and exit --version output version information and exit
例子：
1）删除2,5行
# cat -n /etc/passwd |sed ‘2,5d‘ 1 root:x:0:0:root:/root:/bin/bash 6 sync:x:5:0:sync:/sbin:/bin/sync 7 shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown 8 halt:x:7:0:halt:/sbin:/sbin/halt 9 mail:x:8:12:mail:/var/spool/mail:/sbin/nologin 10 uucp:x:10:14:uucp:/var/spool/uucp:/sbin/nologin
2） 添加 在第2行后添加 hello world
# cat -n /etc/passwd|sed ‘2a hello world‘ 1 root:x:0:0:root:/root:/bin/bash 2 bin:x:1:1:bin:/bin:/sbin/nologin hello world
3）添加2行，在第1行后面添加两行 （以续航符号 \, 按Enter键继续输入，以‘结束）
]# cat -n /etc/passwd|sed ‘1a this is frist line \ > this is second line ‘ 1 root:x:0:0:root:/root:/bin/bash this is frist line this is second line
4) 替换，以2,5行替换成 “我 是 谁”
# cat -n /etc/passwd |sed ‘2,5c 我是谁！ ‘ 1 root:x:0:0:root:/root:/bin/bash 我是谁！ 6 sync:x:5:0:sync:/sbin:/bin/sync
5）显示特定行，只显示5-7行，注意n和p同时使用
# cat -n /etc/passwd |sed -n ‘5,7p‘ 5 lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin 6 sync:x:5:0:sync:/sbin:/bin/sync 7 shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown
6）显示出ifconfig中的ip地址
# ifconfig eth0 | grep ‘inet addr‘ |sed ‘s/^.*addr://g‘ |sed ‘s/Bcast.*$//g‘ 192.168.0.35
# ifconfig eth0 | grep ‘inet addr‘ |awk -F[:] ‘{print $2}‘ | awk ‘{print $1}‘ 192.168.0.35
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2. sed的基础用法
1）删除行首空格
# sed ‘s/^[ ]* //g‘ test.txt zero line first line
# sed ‘s/^ * //g‘ test.txt zero line first line
# sed ‘s/^[[:space:]]* //g‘ test.txt
2）在第一行插入文本
# sed -i ‘1 i\000000‘ test.txt
3）在最后一行插入
# sed -i ‘$ i\endendend0000000‘ test.txt
4）在匹配行前插入
# sed -i ‘/zero/ i the 3 line‘ test.txt
5）在匹配行后插入
sed -i ‘/the end/ a "this is the end line"‘ test.txt
6) 删除空行及行首空格和#号的行
# grep -v ^# test.txt | sed /^[[:space:]]*$/d | sed ‘/^$/d‘
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原文地址：http://www.cnblogs.com/love3556/p/5912274.html
