grep过滤特定的行
1.把包含‘halt’的行以及这行下面的两行都打印出来。
[root@CentOS6 ~]# cp /etc/passwd /tmp/
[root@CentOS6 ~]# cd /tmp/
[root@CentOS6 tmp]# grep -A2 ‘halt‘ passwd
halt:x:7:0:halt:/sbin:/sbin/halt
mail:x:8:12:mail:/var/spool/mail:/sbin/nologin
uucp:x:10:14:uucp:/var/spool/uucp:/sbin/nologin
[root@CentOS6 tmp]#
2.把包含‘halt’的行以及这行上面的两行都打印出来。
[root@CentOS6 tmp]# grep -B2 ‘halt‘ passwd
sync:x:5:0:sync:/sbin:/bin/sync
shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown
halt:x:7:0:halt:/sbin:/sbin/halt
[root@CentOS6 tmp]#
3.把包含‘halt’的行以及这行上面和下面的各两行都打印出来。
[root@CentOS6 tmp]# grep -C2 ‘halt‘ passwd
sync:x:5:0:sync:/sbin:/bin/sync
shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown
halt:x:7:0:halt:/sbin:/sbin/halt
mail:x:8:12:mail:/var/spool/mail:/sbin/nologin
uucp:x:10:14:uucp:/var/spool/uucp:/sbin/nologin
[root@CentOS6 tmp]#
4.过滤出带有关键词‘root’的行并输出行号
[root@CentOS6 tmp]# grep -n ‘root‘ passwd
1:root:x:0:0:root:/root:/bin/bash
11:operator:x:11:0:operator:/root:/sbin/nologin
[root@CentOS6 tmp]#
5.过滤不带关键词‘nologin’的行并输出行号
[root@CentOS6 tmp]# grep -nv ‘nologin‘ passwd
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
21:user1:x:500:500::/tmp/rachy:/bin/bash
22:user12:x:501:501::/home/user12:/bin/bash
23:rachy:x:502:502::/home/rachy:/bin/bash
24:Jack:x:503:503::/home/Jack:/bin/bash
[root@CentOS6 tmp]#
6.过滤出所有包含数字的行
[root@CentOS6 tmp]# cp /etc/inittab .
[root@CentOS6 tmp]# grep ‘[0-9]‘ inittab
# upstart works, see init(5), init(8), and initctl(8).
# 0 - halt (Do NOT set initdefault to this)
# 1 - Single user mode
# 2 - Multiuser, without NFS (The same as 3, if you do not have networking)
# 3 - Full multiuser mode
# 4 - unused
# 5 - X11
# 6 - reboot (Do NOT set initdefault to this)
id:3:initdefault:
[root@CentOS6 tmp]#
7.过滤出所有不含数字的行
[root@CentOS6 tmp]# grep -v ‘[0-9]‘ inittab
# inittab is only used by upstart for the default runlevel.
#
# ADDING OTHER CONFIGURATION HERE WILL HAVE NO EFFECT ON YOUR SYSTEM.
#
# System initialization is started by /etc/init/rcS.conf
#
# Individual runlevels are started by /etc/init/rc.conf
#
# Ctrl-Alt-Delete is handled by /etc/init/control-alt-delete.conf
#
# Terminal gettys are handled by /etc/init/tty.conf and /etc/init/serial.conf,
# with configuration in /etc/sysconfig/init.
#
# For information on how to write upstart event handlers, or how
#
# Default runlevel. The runlevels used are:
#
[root@CentOS6 tmp]#
8.过滤出所有不以“#”开头的行
[root@CentOS6 tmp]# grep -v ‘^#‘ inittab
id:3:initdefault:
[root@CentOS6 tmp]#
9.去掉所有空行和以“#”开头的行
[root@CentOS6 tmp]# cp /etc/crontab .
[root@CentOS6 tmp]# grep -v ‘^#‘ crontab |grep -v ‘^$‘
SHELL=/bin/bash
PATH=/sbin:/bin:/usr/sbin:/usr/bin
MAILTO=root
HOME=/
[root@CentOS6 tmp]#
在正则表达式中“^”表示行的开始，“$”表示行的结尾，那么空行就可以用“^$”表示。
10.打印出不以英文字母开头的行
[root@CentOS6 tmp]# cat test.txt
123
abc
456
abc2323
#laksdjf
Allllll
[root@CentOS6 tmp]# grep ‘^[^a-zA-Z]‘ test.txt #方法1，不包括空行
123
456
#laksdjf
[root@CentOS6 tmp]# grep -v ‘^[a-zA-Z]‘ test.txt #方法2，包括空行（更合适）
123
456
#laksdjf
[root@CentOS6 tmp]#
11.含有非英文字符的行
[root@CentOS6 tmp]# grep ‘[^a-zA-Z]‘ test.txt #方法1，不含空行
123
456
abc2323
#laksdjf
[root@CentOS6 tmp]# grep -v ‘^[a-zA-Z]\+$‘ test.txt #方法2，包括空行（更合适）
123
456
abc2323
#laksdjf
[root@CentOS6 tmp]#
12.过滤含有r..o的行，点表示一个任意字符
[root@CentOS6 tmp]# grep ‘r..o‘ passwd
operator:x:11:0:operator:/root:/sbin/nologin
gopher:x:13:30:gopher:/var/gopher:/sbin/nologin
vcsa:x:69:69:virtual console memory owner:/dev:/sbin/nologin
[root@CentOS6 tmp]#
13.过滤含有ooo*的行，星表示前面字符重复0次或多次，即oo,ooo,oooo,……
[root@CentOS6 tmp]# grep ‘ooo*‘ passwd
root:x:0:0:root:/root:/bin/bash
lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin
mail:x:8:12:mail:/var/spool/mail:/sbin/nologin
uucp:x:10:14:uucp:/var/spool/uucp:/sbin/nologin
operator:x:11:0:operator:/root:/sbin/nologin
postfix:x:89:89::/var/spool/postfix:/sbin/nologin
[root@CentOS6 tmp]#
14.统计passwd文件的行数
[root@CentOS6 tmp]# grep ‘.*‘ passwd |wc -l #方法1，.*表示任意字符重复任意多次
24
[root@CentOS6 tmp]# wc -l passwd #方法2，使用wc命令更简单
24 passwd
[root@CentOS6 tmp]#
15.指定要过滤字符出现的次数
[root@CentOS6 tmp]# grep ‘o\{2\}‘ passwd
root:x:0:0:root:/root:/bin/bash
lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin
mail:x:8:12:mail:/var/spool/mail:/sbin/nologin
uucp:x:10:14:uucp:/var/spool/uucp:/sbin/nologin
operator:x:11:0:operator:/root:/sbin/nologin
postfix:x:89:89::/var/spool/postfix:/sbin/nologin
[root@CentOS6 tmp]#
下面我们来试试egrep
1.筛选一个或多个前面的字符
[root@CentOS6 tmp]# cat test.txt
rot:x:0:0:rot:/rot:/bin/bash
roooot:x:1:1:bin:/bin:/sbin/nologin
daemon:x:2:2:daemon:/root:/sbin/nologin
adm:x:3:4:adm:/var/adm:/sbin/nologin
lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin
sync:x:5:0:sync:/sbin:/bin/sync
1234422798776
dasaddssdfjhalkja
[root@CentOS6 tmp]# egrep ‘o+‘ test.txt #过滤含有至少一个o的行
rot:x:0:0:rot:/rot:/bin/bash
roooot:x:1:1:bin:/bin:/sbin/nologin
daemon:x:2:2:daemon:/root:/sbin/nologin
adm:x:3:4:adm:/var/adm:/sbin/nologin
lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin
[root@CentOS6 tmp]# egrep ‘oo+‘ test.txt #过滤含有至少两个o的行
roooot:x:1:1:bin:/bin:/sbin/nologin
daemon:x:2:2:daemon:/root:/sbin/nologin
lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin
[root@CentOS6 tmp]#
2.筛选零个或一个前面的字符
[root@CentOS6 tmp]# egrep ‘o?‘ test.txt #过滤含有0个或1个o的行
rot:x:0:0:rot:/rot:/bin/bash
roooot:x:1:1:bin:/bin:/sbin/nologin
daemon:x:2:2:daemon:/root:/sbin/nologin
adm:x:3:4:adm:/var/adm:/sbin/nologin
lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin
sync:x:5:0:sync:/sbin:/bin/sync
1234422798776
dasaddssdfjhalkja
[root@CentOS6 tmp]# egrep ‘ooo?‘ test.txt #过滤含有两个或三个o的行
roooot:x:1:1:bin:/bin:/sbin/nologin
daemon:x:2:2:daemon:/root:/sbin/nologin
lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin
[root@CentOS6 tmp]#
3.筛选字符串1或字符串2
[root@CentOS6 tmp]# egrep ‘sbin|22|nologin‘ test.txt
roooot:x:1:1:bin:/bin:/sbin/nologin
daemon:x:2:2:daemon:/root:/sbin/nologin
adm:x:3:4:adm:/var/adm:/sbin/nologin
lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin
sync:x:5:0:sync:/sbin:/bin/sync
1234422798776
[root@CentOS6 tmp]#
4.egrep中（）的应用
[root@CentOS6 tmp]# egrep ‘r(oo)|(at)o‘ test.txt
root:x:0:0:root:/root:/bin/bash
rooot:x:0:0:root:/root:/bin/bash
root:x:0:0:roooooooot:/root:/bin/bash
operator:x:11:0:operator:/root:/sbin/nologin
[root@CentOS6 tmp]#
5.用（）表示一个整体，例如(oo)+表示1个或多个‘oo’
[root@CentOS6 tmp]# egrep ‘(oo)+‘ test.txt
root:x:0:0:root:/root:/bin/bash
rooot:x:0:0:root:/root:/bin/bash
root:x:0:0:roooooooot:/root:/bin/bash
lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin
mail:x:8:12:mail:/var/spool/mail:/sbin/nologin
uucp:x:10:14:uucp:/var/spool/uucp:/sbin/nologin
operator:x:11:0:operator:/root:/sbin/nologin
postfix:x:89:89::/var/spool/postfix:/sbin/nologin
[root@CentOS6 tmp]#
sed工具的使用
1.打印指定的行
[root@CentOS6 tmp]# sed -n ‘2‘p passwd
bin:x:1:1:bin:/bin:/sbin/nologin
[root@CentOS6 tmp]#
2.打印所有行
[root@CentOS6 tmp]# sed -n ‘1,$‘p passwd
root:x:0:0:root:/root:/bin/bash
bin:x:1:1:bin:/bin:/sbin/nologin
daemon:x:2:2:daemon:/sbin:/sbin/nologin
adm:x:3:4:adm:/var/adm:/sbin/nologin
lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin
sync:x:5:0:sync:/sbin:/bin/sync
shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown
halt:x:7:0:halt:/sbin:/sbin/halt
mail:x:8:12:mail:/var/spool/mail:/sbin/nologin
uucp:x:10:14:uucp:/var/spool/uucp:/sbin/nologin
operator:x:11:0:operator:/root:/sbin/nologin
games:x:12:100:games:/usr/games:/sbin/nologin
gopher:x:13:30:gopher:/var/gopher:/sbin/nologin
ftp:x:14:50:FTP User:/var/ftp:/sbin/nologin
nobody:x:99:99:Nobody:/:/sbin/nologin
dbus:x:81:81:System message bus:/:/sbin/nologin
vcsa:x:69:69:virtual console memory owner:/dev:/sbin/nologin
saslauth:x:499:76:"Saslauthd user":/var/empty/saslauth:/sbin/nologin
postfix:x:89:89::/var/spool/postfix:/sbin/nologin
sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin
user1:x:500:500::/tmp/rachy:/bin/bash
user12:x:501:501::/home/user12:/bin/bash
rachy:x:502:502::/home/rachy:/bin/bash
Jack:x:503:503::/home/Jack:/bin/bash
[root@CentOS6 tmp]#
3.可以指定一个区间
[root@CentOS6 tmp]# sed -n ‘1,3‘p passwd
root:x:0:0:root:/root:/bin/bash
bin:x:1:1:bin:/bin:/sbin/nologin
daemon:x:2:2:daemon:/sbin:/sbin/nologin
[root@CentOS6 tmp]#
4.打印包含指定字符串的行
[root@CentOS6 tmp]# sed -n ‘/root/‘p passwd
root:x:0:0:root:/root:/bin/bash
operator:x:11:0:operator:/root:/sbin/nologin
[root@CentOS6 tmp]#
5.grep中使用的特殊字符，如^$.*等同样也能在sed中使用
[root@CentOS6 tmp]# sed -n ‘/^r/‘p passwd
root:x:0:0:root:/root:/bin/bash
rachy:x:502:502::/home/rachy:/bin/bash
[root@CentOS6 tmp]# sed -n ‘/in$/‘p passwd
bin:x:1:1:bin:/bin:/sbin/nologin
daemon:x:2:2:daemon:/sbin:/sbin/nologin
adm:x:3:4:adm:/var/adm:/sbin/nologin
lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin
mail:x:8:12:mail:/var/spool/mail:/sbin/nologin
uucp:x:10:14:uucp:/var/spool/uucp:/sbin/nologin
operator:x:11:0:operator:/root:/sbin/nologin
games:x:12:100:games:/usr/games:/sbin/nologin
gopher:x:13:30:gopher:/var/gopher:/sbin/nologin
ftp:x:14:50:FTP User:/var/ftp:/sbin/nologin
nobody:x:99:99:Nobody:/:/sbin/nologin
dbus:x:81:81:System message bus:/:/sbin/nologin
vcsa:x:69:69:virtual console memory owner:/dev:/sbin/nologin
saslauth:x:499:76:"Saslauthd user":/var/empty/saslauth:/sbin/nologin
postfix:x:89:89::/var/spool/postfix:/sbin/nologin
sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin
[root@CentOS6 tmp]# sed -n ‘/r..o/‘p passwd
operator:x:11:0:operator:/root:/sbin/nologin
gopher:x:13:30:gopher:/var/gopher:/sbin/nologin
vcsa:x:69:69:virtual console memory owner:/dev:/sbin/nologin
[root@CentOS6 tmp]# sed -n ‘/oo*/‘p passwd
root:x:0:0:root:/root:/bin/bash
bin:x:1:1:bin:/bin:/sbin/nologin
daemon:x:2:2:daemon:/sbin:/sbin/nologin
adm:x:3:4:adm:/var/adm:/sbin/nologin
lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin
shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown
mail:x:8:12:mail:/var/spool/mail:/sbin/nologin
uucp:x:10:14:uucp:/var/spool/uucp:/sbin/nologin
operator:x:11:0:operator:/root:/sbin/nologin
games:x:12:100:games:/usr/games:/sbin/nologin
gopher:x:13:30:gopher:/var/gopher:/sbin/nologin
ftp:x:14:50:FTP User:/var/ftp:/sbin/nologin
nobody:x:99:99:Nobody:/:/sbin/nologin
dbus:x:81:81:System message bus:/:/sbin/nologin
vcsa:x:69:69:virtual console memory owner:/dev:/sbin/nologin
saslauth:x:499:76:"Saslauthd user":/var/empty/saslauth:/sbin/nologin
postfix:x:89:89::/var/spool/postfix:/sbin/nologin
sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin
user12:x:501:501::/home/user12:/bin/bash
rachy:x:502:502::/home/rachy:/bin/bash
Jack:x:503:503::/home/Jack:/bin/bash
6.使用-e选项可以实现多个行为
[root@CentOS6 tmp]# sed -e ‘1‘p -e ‘/rachy/‘p -n passwd
root:x:0:0:root:/root:/bin/bash
user1:x:500:500::/tmp/rachy:/bin/bash
rachy:x:502:502::/home/rachy:/bin/bash
[root@CentOS6 tmp]#
7.删除一行或多行
[root@CentOS6 tmp]# sed ‘1‘d passwd
bin:x:1:1:bin:/bin:/sbin/nologin
daemon:x:2:2:daemon:/sbin:/sbin/nologin
adm:x:3:4:adm:/var/adm:/sbin/nologin
lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin
sync:x:5:0:sync:/sbin:/bin/sync
shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown
halt:x:7:0:halt:/sbin:/sbin/halt
mail:x:8:12:mail:/var/spool/mail:/sbin/nologin
uucp:x:10:14:uucp:/var/spool/uucp:/sbin/nologin
operator:x:11:0:operator:/root:/sbin/nologin
games:x:12:100:games:/usr/games:/sbin/nologin
gopher:x:13:30:gopher:/var/gopher:/sbin/nologin
ftp:x:14:50:FTP User:/var/ftp:/sbin/nologin
nobody:x:99:99:Nobody:/:/sbin/nologin
dbus:x:81:81:System message bus:/:/sbin/nologin
vcsa:x:69:69:virtual console memory owner:/dev:/sbin/nologin
saslauth:x:499:76:"Saslauthd user":/var/empty/saslauth:/sbin/nologin
postfix:x:89:89::/var/spool/postfix:/sbin/nologin
sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin
user1:x:500:500::/tmp/rachy:/bin/bash
user12:x:501:501::/home/user12:/bin/bash
rachy:x:502:502::/home/rachy:/bin/bash
Jack:x:503:503::/home/Jack:/bin/bash
[root@CentOS6 tmp]# sed ‘1,3‘d passwd
adm:x:3:4:adm:/var/adm:/sbin/nologin
lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin
sync:x:5:0:sync:/sbin:/bin/sync
shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown
halt:x:7:0:halt:/sbin:/sbin/halt
mail:x:8:12:mail:/var/spool/mail:/sbin/nologin
uucp:x:10:14:uucp:/var/spool/uucp:/sbin/nologin
operator:x:11:0:operator:/root:/sbin/nologin
games:x:12:100:games:/usr/games:/sbin/nologin
gopher:x:13:30:gopher:/var/gopher:/sbin/nologin
ftp:x:14:50:FTP User:/var/ftp:/sbin/nologin
nobody:x:99:99:Nobody:/:/sbin/nologin
dbus:x:81:81:System message bus:/:/sbin/nologin
vcsa:x:69:69:virtual console memory owner:/dev:/sbin/nologin
saslauth:x:499:76:"Saslauthd user":/var/empty/saslauth:/sbin/nologin
postfix:x:89:89::/var/spool/postfix:/sbin/nologin
sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin
user1:x:500:500::/tmp/rachy:/bin/bash
user12:x:501:501::/home/user12:/bin/bash
rachy:x:502:502::/home/rachy:/bin/bash
Jack:x:503:503::/home/Jack:/bin/bash
[root@CentOS6 tmp]# sed ‘/root/‘d passwd
bin:x:1:1:bin:/bin:/sbin/nologin
daemon:x:2:2:daemon:/sbin:/sbin/nologin
adm:x:3:4:adm:/var/adm:/sbin/nologin
lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin
sync:x:5:0:sync:/sbin:/bin/sync
shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown
halt:x:7:0:halt:/sbin:/sbin/halt
mail:x:8:12:mail:/var/spool/mail:/sbin/nologin
uucp:x:10:14:uucp:/var/spool/uucp:/sbin/nologin
games:x:12:100:games:/usr/games:/sbin/nologin
gopher:x:13:30:gopher:/var/gopher:/sbin/nologin
ftp:x:14:50:FTP User:/var/ftp:/sbin/nologin
nobody:x:99:99:Nobody:/:/sbin/nologin
dbus:x:81:81:System message bus:/:/sbin/nologin
vcsa:x:69:69:virtual console memory owner:/dev:/sbin/nologin
saslauth:x:499:76:"Saslauthd user":/var/empty/saslauth:/sbin/nologin
postfix:x:89:89::/var/spool/postfix:/sbin/nologin
sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin
user1:x:500:500::/tmp/rachy:/bin/bash
user12:x:501:501::/home/user12:/bin/bash
rachy:x:502:502::/home/rachy:/bin/bash
Jack:x:503:503::/home/Jack:/bin/bash
[root@CentOS6 tmp]#
8.替换字符或字符串
[root@CentOS6 tmp]# sed ‘1,2s/root/rachy/g‘ passwd
rachy:x:0:0:rachy:/rachy:/bin/bash
bin:x:1:1:bin:/bin:/sbin/nologin
daemon:x:2:2:daemon:/sbin:/sbin/nologin
adm:x:3:4:adm:/var/adm:/sbin/nologin
lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin
sync:x:5:0:sync:/sbin:/bin/sync
shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown
halt:x:7:0:halt:/sbin:/sbin/halt
mail:x:8:12:mail:/var/spool/mail:/sbin/nologin
uucp:x:10:14:uucp:/var/spool/uucp:/sbin/nologin
operator:x:11:0:operator:/root:/sbin/nologin
games:x:12:100:games:/usr/games:/sbin/nologin
gopher:x:13:30:gopher:/var/gopher:/sbin/nologin
ftp:x:14:50:FTP User:/var/ftp:/sbin/nologin
nobody:x:99:99:Nobody:/:/sbin/nologin
dbus:x:81:81:System message bus:/:/sbin/nologin
vcsa:x:69:69:virtual console memory owner:/dev:/sbin/nologin
saslauth:x:499:76:"Saslauthd user":/var/empty/saslauth:/sbin/nologin
postfix:x:89:89::/var/spool/postfix:/sbin/nologin
sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin
user1:x:500:500::/tmp/rachy:/bin/bash
user12:x:501:501::/home/user12:/bin/bash
rachy:x:502:502::/home/rachy:/bin/bash
Jack:x:503:503::/home/Jack:/bin/bash
[root@CentOS6 tmp]# sed ‘s#nologin#login#g‘ passwd
root:x:0:0:root:/root:/bin/bash
bin:x:1:1:bin:/bin:/sbin/login
daemon:x:2:2:daemon:/sbin:/sbin/login
adm:x:3:4:adm:/var/adm:/sbin/login
lp:x:4:7:lp:/var/spool/lpd:/sbin/login
sync:x:5:0:sync:/sbin:/bin/sync
shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown
halt:x:7:0:halt:/sbin:/sbin/halt
mail:x:8:12:mail:/var/spool/mail:/sbin/login
uucp:x:10:14:uucp:/var/spool/uucp:/sbin/login
operator:x:11:0:operator:/root:/sbin/login
games:x:12:100:games:/usr/games:/sbin/login
gopher:x:13:30:gopher:/var/gopher:/sbin/login
ftp:x:14:50:FTP User:/var/ftp:/sbin/login
nobody:x:99:99:Nobody:/:/sbin/login
dbus:x:81:81:System message bus:/:/sbin/login
vcsa:x:69:69:virtual console memory owner:/dev:/sbin/login
saslauth:x:499:76:"Saslauthd user":/var/empty/saslauth:/sbin/login
postfix:x:89:89::/var/spool/postfix:/sbin/login
sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/login
user1:x:500:500::/tmp/rachy:/bin/bash
user12:x:501:501::/home/user12:/bin/bash
rachy:x:502:502::/home/rachy:/bin/bash
Jack:x:503:503::/home/Jack:/bin/bash
[root@CentOS6 tmp]# sed ‘s@nologin@false@g‘ passwd
root:x:0:0:root:/root:/bin/bash
bin:x:1:1:bin:/bin:/sbin/false
daemon:x:2:2:daemon:/sbin:/sbin/false
adm:x:3:4:adm:/var/adm:/sbin/false
lp:x:4:7:lp:/var/spool/lpd:/sbin/false
sync:x:5:0:sync:/sbin:/bin/sync
shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown
halt:x:7:0:halt:/sbin:/sbin/halt
mail:x:8:12:mail:/var/spool/mail:/sbin/false
uucp:x:10:14:uucp:/var/spool/uucp:/sbin/false
operator:x:11:0:operator:/root:/sbin/false
games:x:12:100:games:/usr/games:/sbin/false
gopher:x:13:30:gopher:/var/gopher:/sbin/false
ftp:x:14:50:FTP User:/var/ftp:/sbin/false
nobody:x:99:99:Nobody:/:/sbin/false
dbus:x:81:81:System message bus:/:/sbin/false
vcsa:x:69:69:virtual console memory owner:/dev:/sbin/false
saslauth:x:499:76:"Saslauthd user":/var/empty/saslauth:/sbin/false
postfix:x:89:89::/var/spool/postfix:/sbin/false
sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/false
user1:x:500:500::/tmp/rachy:/bin/bash
user12:x:501:501::/home/user12:/bin/bash
rachy:x:502:502::/home/rachy:/bin/bash
Jack:x:503:503::/home/Jack:/bin/bash
[root@CentOS6 tmp]# sed ‘s/[0-9]//g‘ passwd
root:x:::root:/root:/bin/bash
bin:x:::bin:/bin:/sbin/nologin
daemon:x:::daemon:/sbin:/sbin/nologin
adm:x:::adm:/var/adm:/sbin/nologin
lp:x:::lp:/var/spool/lpd:/sbin/nologin
sync:x:::sync:/sbin:/bin/sync
shutdown:x:::shutdown:/sbin:/sbin/shutdown
halt:x:::halt:/sbin:/sbin/halt
mail:x:::mail:/var/spool/mail:/sbin/nologin
uucp:x:::uucp:/var/spool/uucp:/sbin/nologin
operator:x:::operator:/root:/sbin/nologin
games:x:::games:/usr/games:/sbin/nologin
gopher:x:::gopher:/var/gopher:/sbin/nologin
ftp:x:::FTP User:/var/ftp:/sbin/nologin
nobody:x:::Nobody:/:/sbin/nologin
dbus:x:::System message bus:/:/sbin/nologin
vcsa:x:::virtual console memory owner:/dev:/sbin/nologin
saslauth:x:::"Saslauthd user":/var/empty/saslauth:/sbin/nologin
postfix:x::::/var/spool/postfix:/sbin/nologin
sshd:x:::Privilege-separated SSH:/var/empty/sshd:/sbin/nologin
user:x::::/tmp/rachy:/bin/bash
user:x::::/home/user:/bin/bash
rachy:x::::/home/rachy:/bin/bash
Jack:x::::/home/Jack:/bin/bash
[root@CentOS6 tmp]# sed ‘s/[a-zA-Z]//g‘ passwd
::0:0::/://
::1:1::/://
::2:2::/://
::3:4:://://
::4:7::///://
::5:0::/://
::6:0::/://
::7:0::/://
::8:12::///://
::10:14::///://
::11:0::/://
::12:100:://://
::13:30:://://
::14:50: ://://
::99:99::/://
::81:81: :/://
::69:69: :/://
::499:76:" ":///://
::89:89::///://
::74:74:- :///://
1::500:500:://://
12::501:501:://12://
::502:502:://://
::503:503:://://
[root@CentOS6 tmp]#
9.调换两个字符串的位置
[root@CentOS6 tmp]# sed ‘s/\(root\)\(.*\)\(bash\)/\3\2\1/‘ passwd
bash:x:0:0:root:/root:/bin/root
bin:x:1:1:bin:/bin:/sbin/nologin
daemon:x:2:2:daemon:/sbin:/sbin/nologin
adm:x:3:4:adm:/var/adm:/sbin/nologin
lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin
sync:x:5:0:sync:/sbin:/bin/sync
shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown
halt:x:7:0:halt:/sbin:/sbin/halt
mail:x:8:12:mail:/var/spool/mail:/sbin/nologin
uucp:x:10:14:uucp:/var/spool/uucp:/sbin/nologin
operator:x:11:0:operator:/root:/sbin/nologin
games:x:12:100:games:/usr/games:/sbin/nologin
gopher:x:13:30:gopher:/var/gopher:/sbin/nologin
ftp:x:14:50:FTP User:/var/ftp:/sbin/nologin
nobody:x:99:99:Nobody:/:/sbin/nologin
dbus:x:81:81:System message bus:/:/sbin/nologin
vcsa:x:69:69:virtual console memory owner:/dev:/sbin/nologin
saslauth:x:499:76:"Saslauthd user":/var/empty/saslauth:/sbin/nologin
postfix:x:89:89::/var/spool/postfix:/sbin/nologin
sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin
user1:x:500:500::/tmp/rachy:/bin/bash
user12:x:501:501::/home/user12:/bin/bash
rachy:x:502:502::/home/rachy:/bin/bash
Jack:x:503:503::/home/Jack:/bin/bash
[root@CentOS6 tmp]# sed ‘s/^.*$/123&/‘ passwd
123root:x:0:0:root:/root:/bin/bash
123bin:x:1:1:bin:/bin:/sbin/nologin
123daemon:x:2:2:daemon:/sbin:/sbin/nologin
123adm:x:3:4:adm:/var/adm:/sbin/nologin
123lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin
123sync:x:5:0:sync:/sbin:/bin/sync
123shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown
123halt:x:7:0:halt:/sbin:/sbin/halt
123mail:x:8:12:mail:/var/spool/mail:/sbin/nologin
123uucp:x:10:14:uucp:/var/spool/uucp:/sbin/nologin
123operator:x:11:0:operator:/root:/sbin/nologin
123games:x:12:100:games:/usr/games:/sbin/nologin
123gopher:x:13:30:gopher:/var/gopher:/sbin/nologin
123ftp:x:14:50:FTP User:/var/ftp:/sbin/nologin
123nobody:x:99:99:Nobody:/:/sbin/nologin
123dbus:x:81:81:System message bus:/:/sbin/nologin
123vcsa:x:69:69:virtual console memory owner:/dev:/sbin/nologin
123saslauth:x:499:76:"Saslauthd user":/var/empty/saslauth:/sbin/nologin
123postfix:x:89:89::/var/spool/postfix:/sbin/nologin
123sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin
123user1:x:500:500::/tmp/rachy:/bin/bash
123user12:x:501:501::/home/user12:/bin/bash
123rachy:x:502:502::/home/rachy:/bin/bash
123Jack:x:503:503::/home/Jack:/bin/bash
10.直接修改文件内容
[root@CentOS6 tmp]# sed -i ‘s/root/rachy/g‘ passwd
[root@CentOS6 tmp]# cat passwd
rachy:x:0:0:rachy:/rachy:/bin/bash
bin:x:1:1:bin:/bin:/sbin/nologin
daemon:x:2:2:daemon:/sbin:/sbin/nologin
adm:x:3:4:adm:/var/adm:/sbin/nologin
lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin
sync:x:5:0:sync:/sbin:/bin/sync
shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown
halt:x:7:0:halt:/sbin:/sbin/halt
mail:x:8:12:mail:/var/spool/mail:/sbin/nologin
uucp:x:10:14:uucp:/var/spool/uucp:/sbin/nologin
operator:x:11:0:operator:/rachy:/sbin/nologin
games:x:12:100:games:/usr/games:/sbin/nologin
gopher:x:13:30:gopher:/var/gopher:/sbin/nologin
ftp:x:14:50:FTP User:/var/ftp:/sbin/nologin
nobody:x:99:99:Nobody:/:/sbin/nologin
dbus:x:81:81:System message bus:/:/sbin/nologin
vcsa:x:69:69:virtual console memory owner:/dev:/sbin/nologin
saslauth:x:499:76:"Saslauthd user":/var/empty/saslauth:/sbin/nologin
postfix:x:89:89::/var/spool/postfix:/sbin/nologin
sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin
user1:x:500:500::/tmp/rachy:/bin/bash
user12:x:501:501::/home/user12:/bin/bash
rachy:x:502:502::/home/rachy:/bin/bash
Jack:x:503:503::/home/Jack:/bin/bash
[root@CentOS6 tmp]#
sed练习题：
1.把/etc/passwd复制到/tmp/test.txt，用sed打印所有行
[root@CentOS6 tmp]# cp /etc/passwd /tmp/test.txt
[root@CentOS6 tmp]# sed -n p test.txt #方法1
[root@CentOS6 tmp]# sed -n ‘1,$‘p test.txt #方法2
2.打印test.txt的3到10行
[root@CentOS6 tmp]# sed -n ‘3,10‘p test.txt
3.打印test.txt中包含root的行
[root@CentOS6 tmp]# sed -n ‘/root/‘p test.txt
4.删除test.txt中15行及以后所有行
[root@CentOS6 tmp]# sed ‘15,$‘d test.txt
5.删除test.txt中包含bash的行
[root@CentOS6 tmp]# sed ‘/bash/‘d test.txt
6.替换test.txt中的root为rachy
[root@CentOS6 tmp]# sed ‘s/root/rachy/g‘ test.txt
7.替换test.txt中的/sbin/nologin为/bin/login
[root@CentOS6 tmp]# sed ‘s#/sbin/nologin#/bin/login#g‘ test.txt #方法1
[root@CentOS6 tmp]# sed ‘s@/sbin/nologin@/bin/login#g‘ test.txt #方法2
[root@CentOS6 tmp]# sed ‘s/\/sbin\/nologin/\/bin\/login/g‘ test.txt #方法3
8.删除test.txt中5到10行所有数字
[root@CentOS6 tmp]# sed ‘5,10s/[0-9]//g‘ test.txt
9.删除test.txt所有特殊字符（除了数字和大小写字母）
[root@CentOS6 tmp]# sed ‘s/[^0-9a-zA-Z]//g‘ test.txt
10.把test.txt中第一个单词和最后一个单词调换位置
[root@CentOS6 tmp]# sed ‘s/\(^[a-zA-Z]\+\)\([^a-zA-Z].*\)\([^a-zA-Z]\)\([a-zA-Z]*$\)/\4\2\3\1/‘ test.txt #方法1
[root@CentOS6 tmp]# sed ‘s/\(^[a-zA-Z][a-zA-Z]*\)\([^a-zA-Z].*\)\([^a-zA-Z]\)\([a-zA-Z]*$\)/\4\2\3\1/‘ test.txt #方法2
11.把test.txt中出现的第一个数字和最后一个单词互换位置
[root@CentOS6 tmp]# sed ‘s/\([^0-9][^0-9]*\)\([0-9][0-9]*\)\([^0-9].*\)\([^a-zA-Z]\)\([a-zA-Z][a-zA-Z]*$\)/\1\5\3\4\2/‘ test.txt #方法1
[root@CentOS6 tmp]# sed ‘s/\([^0-9]*\)\([0-9]\+\)\([^0-9].*\)\([^0-9a-zA-Z]\)\([a-zA-Z]\+$\)/\1\5\3\4\2/‘ test.txt #方法2
12.把test.txt中第一个数字移动到行末尾
[root@CentOS6 tmp]# sed ‘s/\([^0-9][^0-9]*\)\([0-9]*\)\([^0-9][^0-9]*$\)/\1\3\2/‘ test.txt
[root@CentOS6 tmp]# sed ‘s/\([^0-9]*\)\([0-9]\+\)\([^0-9].*$\)/\1\3\2/‘ test.txt
13.在test.txt中20行到末行最前面加aaa:
[root@CentOS6 tmp]# sed ‘20,$s/^.*$/aaa:&/‘ test.txt
awk工具的使用
1.截取文档中的某个段
[root@CentOS6 tmp]# head -n 2 passwd |awk -F ‘:‘ ‘{print $1}‘
root
bin
[root@CentOS6 tmp]# head -n 2 passwd |awk -F ‘:‘ ‘{print $0}‘
root:x:0:0:root:/root:/bin/bash
bin:x:1:1:bin:/bin:/sbin/nologin
[root@CentOS6 tmp]# head -n 2 passwd |awk -F ‘:‘ ‘{print $1"#"$2"#"$3}‘
root#x#0
bin#x#1
[root@CentOS6 tmp]#
2.匹配字符或字符串
[root@CentOS6 tmp]# awk ‘/oo/‘ test.txt
root:x:0:0:root:/root:/bin/bash
lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin
mail:x:8:12:mail:/var/spool/mail:/sbin/nologin
uucp:x:10:14:uucp:/var/spool/uucp:/sbin/nologin
operator:x:11:0:operator:/root:/sbin/nologin
postfix:x:89:89::/var/spool/postfix:/sbin/nologin
[root@CentOS6 tmp]# awk -F ‘:‘ ‘$1~/oo/‘ test.txt
root:x:0:0:root:/root:/bin/bash
[root@CentOS6 tmp]# awk -F ‘:‘ ‘/root/ {print $1,$3} /rachy/ {print $1,$3}‘ passwd
root 0
operator 11
user1 500
rachy 502
[root@CentOS6 tmp]#
3.条件操作符
[root@CentOS6 tmp]# awk -F ‘:‘ ‘$3=="0"‘ passwd
root:x:0:0:root:/root:/bin/bash
[root@CentOS6 tmp]# awk -F ‘:‘ ‘$3==0‘ passwd
root:x:0:0:root:/root:/bin/bash
[root@CentOS6 tmp]# awk -F ‘:‘ ‘$3>="500"‘ passwd
shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown
halt:x:7:0:halt:/sbin:/sbin/halt
mail:x:8:12:mail:/var/spool/mail:/sbin/nologin
nobody:x:99:99:Nobody:/:/sbin/nologin
dbus:x:81:81:System message bus:/:/sbin/nologin
vcsa:x:69:69:virtual console memory owner:/dev:/sbin/nologin
postfix:x:89:89::/var/spool/postfix:/sbin/nologin
sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin
user1:x:500:500::/tmp/rachy:/bin/bash
user12:x:501:501::/home/user12:/bin/bash
rachy:x:502:502::/home/rachy:/bin/bash
Jack:x:503:503::/home/Jack:/bin/bash
[root@CentOS6 tmp]# awk -F ‘:‘ ‘$7!="/sbin/nologin"‘ passwd
root:x:0:0:root:/root:/bin/bash
sync:x:5:0:sync:/sbin:/bin/sync
shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown
halt:x:7:0:halt:/sbin:/sbin/halt
user1:x:500:500::/tmp/rachy:/bin/bash
user12:x:501:501::/home/user12:/bin/bash
rachy:x:502:502::/home/rachy:/bin/bash
Jack:x:503:503::/home/Jack:/bin/bash
[root@CentOS6 tmp]# awk -F ‘:‘ ‘$3<$4‘ passwd
adm:x:3:4:adm:/var/adm:/sbin/nologin
lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin
mail:x:8:12:mail:/var/spool/mail:/sbin/nologin
uucp:x:10:14:uucp:/var/spool/uucp:/sbin/nologin
games:x:12:100:games:/usr/games:/sbin/nologin
gopher:x:13:30:gopher:/var/gopher:/sbin/nologin
ftp:x:14:50:FTP User:/var/ftp:/sbin/nologin
[root@CentOS6 tmp]# awk -F ‘:‘ ‘$3>"5" && $3<"7"‘ passwd
shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown
vcsa:x:69:69:virtual console memory owner:/dev:/sbin/nologin
user1:x:500:500::/tmp/rachy:/bin/bash
user12:x:501:501::/home/user12:/bin/bash
rachy:x:502:502::/home/rachy:/bin/bash
Jack:x:503:503::/home/Jack:/bin/bash
[root@CentOS6 tmp]# awk -F ‘:‘ ‘$3>"5" || $7=="/bin/bash"‘ passwd
root:x:0:0:root:/root:/bin/bash
shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown
halt:x:7:0:halt:/sbin:/sbin/halt
mail:x:8:12:mail:/var/spool/mail:/sbin/nologin
nobody:x:99:99:Nobody:/:/sbin/nologin
dbus:x:81:81:System message bus:/:/sbin/nologin
vcsa:x:69:69:virtual console memory owner:/dev:/sbin/nologin
postfix:x:89:89::/var/spool/postfix:/sbin/nologin
sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin
user1:x:500:500::/tmp/rachy:/bin/bash
user12:x:501:501::/home/user12:/bin/bash
rachy:x:502:502::/home/rachy:/bin/bash
Jack:x:503:503::/home/Jack:/bin/bash
4.awk的内置变量
[root@CentOS6 tmp]# head -n3 passwd |awk -F ‘:‘ ‘{print NF}‘
7
7
7
[root@CentOS6 tmp]# head -n3 passwd |awk -F ‘:‘ ‘{print $NF}‘
/bin/bash
/sbin/nologin
/sbin/nologin
[root@CentOS6 tmp]# head -n3 passwd |awk -F ‘:‘ ‘{print NR}‘
1
2
3
[root@CentOS6 tmp]# awk ‘NR>20‘ passwd
user1:x:500:500::/tmp/rachy:/bin/bash
user12:x:501:501::/home/user12:/bin/bash
rachy:x:502:502::/home/rachy:/bin/bash
Jack:x:503:503::/home/Jack:/bin/bash
[root@CentOS6 tmp]# awk ‘NR>20 && $1~/rachy/‘ passwd
user1:x:500:500::/tmp/rachy:/bin/bash
rachy:x:502:502::/home/rachy:/bin/bash
[root@CentOS6 tmp]#
5.awk中的数学运算
[root@CentOS6 tmp]# head -n3 passwd |awk -F ‘:‘ ‘$1="root"‘
root x 0 0 root /root /bin/bash
root x 1 1 bin /bin /sbin/nologin
root x 2 2 daemon /sbin /sbin/nologin
[root@CentOS6 tmp]# head -n2 passwd
root:x:0:0:root:/root:/bin/bash
bin:x:1:1:bin:/bin:/sbin/nologin
[root@CentOS6 tmp]# head -n2 passwd |awk -F ‘:‘ ‘{$7=$3+$4}‘
[root@CentOS6 tmp]# head -n2 passwd |awk -F ‘:‘ ‘{$7=$3+$4;print $0}‘
root x 0 0 root /root 0
bin x 1 1 bin /bin 2
[root@CentOS6 tmp]# awk -F ‘:‘ ‘{(tol=tol+$3)};END {print tol}‘ passwd
3013
[root@CentOS6 tmp]# awk -F ‘:‘ ‘{if($1=="root")print $0}‘ passwd
root:x:0:0:root:/root:/bin/bash
[root@CentOS6 tmp]#
awk练习题：
1.用awk打印整个test.txt
[root@CentOS6 tmp]# awk ‘{print $0}‘ passwd
2.查找所有包含bash的行
[root@CentOS6 tmp]# awk ‘/bash/‘ test.txt
3.用“：”作分隔符，查找第三段等于0的行
[root@CentOS6 tmp]# awk -F ‘:‘ ‘$3==0‘ test.txt
4.用“：”作分隔符，查找第一段为“root”的行，并把该段的“root”换成“toor”（可以连同sed一起使用）
[root@CentOS6 tmp]# awk -F ‘:‘ ‘$1=="root"‘ test.txt |sed ‘s/root/toor/‘
5.用“：”作分隔符，打印最后一段
[root@CentOS6 tmp]# awk -F ‘:‘ ‘{print $NF}‘ test.txt
6.打印行数大于20的所有行
[root@CentOS6 tmp]# awk -F ‘:‘ ‘NR>20‘ test.txt
7.用“：”作分隔符，打印所有第三段小于第四段的行
[root@CentOS6 tmp]# awk -F ‘:‘ ‘$3<$4‘ test.txt
8.用“：”作分隔符，打印第一段以及最后一段，并且中间用@连接
[root@CentOS6 tmp]# awk -F ‘:‘ ‘{print $1"@"$NF}‘ test.txt #方法1
[root@CentOS6 tmp]# awk -F ‘:‘ ‘OFS="@" {print $1,$NF}‘ test.txt #方法2
9.用“：”作分隔符，把整个文档的第四段相加，求和
[root@CentOS6 tmp]# awk -F ‘:‘ ‘{sum=sum+$4};END {print sum}‘ test.txt
原文地址：http://rachy.blog.51cto.com/11428504/1886717
