grep
- grep [-cinvABC] 'word' filename
- -c 行数
- -i 不区分大小写
- -n 显示行好
- -v 取反
- -r 递归遍历所有子目录
- -A 后面跟数字,过滤出符合要求的行以及下面n行
- -B 同上,过滤出要求的行以上面n行
- -C 同上,同时过滤出符合要求的行以及上下各n行
[root@localhost ~]# mkdir grep
[root@localhost ~]# cd grep
[root@localhost grep]# cp /etc/passwd .
[root@localhost grep]# ls
passwd
[root@localhost grep]# pwd
/root/grep
[root@localhost grep]# grep 'nologin' 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
operator:x:11:0:operator:/root:/sbin/nologin
games:x:12:100:games:/usr/games:/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
polkitd:x:999:998:User for polkitd:/:/sbin/nologin
avahi:x:70:70:Avahi mDNS/DNS-SD Stack:/var/run/avahi-daemon:/sbin/nologin
avahi-autoipd:x:170:170:Avahi IPv4LL Stack:/var/lib/avahi-autoipd:/sbin/nologin
postfix:x:89:89::/var/spool/postfix:/sbin/nologin
sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin
[root@localhost grep]# which grep
alias grep='grep --color=auto'
/usr/bin/grep
[root@localhost grep]# /usr/bin/grep 'nologin' 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
operator:x:11:0:operator:/root:/sbin/nologin
games:x:12:100:games:/usr/games:/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
polkitd:x:999:998:User for polkitd:/:/sbin/nologin
avahi:x:70:70:Avahi mDNS/DNS-SD Stack:/var/run/avahi-daemon:/sbin/nologin
avahi-autoipd:x:170:170:Avahi IPv4LL Stack:/var/lib/avahi-autoipd:/sbin/nologin
postfix:x:89:89::/var/spool/postfix:/sbin/nologin
sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin
由于grep命令自带--color=auto颜色标识,过滤出来自动标明。若使用绝对路径/usr/bin/grep则没有颜色标明。
行数-c
[root@localhost grep]# grep -c 'nologin' passwd
15
显示行号-n
[root@localhost grep]# grep -n 'nologin' passwd
2:bin:x:1:1:bin:/bin:/sbin/nologin
3:daemon:x:2:2:daemon:/sbin:/sbin/nologin
4:adm:x:3:4:adm:/var/adm:/sbin/nologin
5:lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin
9:mail:x:8:12:mail:/var/spool/mail:/sbin/nologin
10:operator:x:11:0:operator:/root:/sbin/nologin
11:games:x:12:100:games:/usr/games:/sbin/nologin
12:ftp:x:14:50:FTP User:/var/ftp:/sbin/nologin
13:nobody:x:99:99:Nobody:/:/sbin/nologin
14:dbus:x:81:81:System message bus:/:/sbin/nologin
15:polkitd:x:999:998:User for polkitd:/:/sbin/nologin
16:avahi:x:70:70:Avahi mDNS/DNS-SD Stack:/var/run/avahi-daemon:/sbin/nologin
17:avahi-autoipd:x:170:170:Avahi IPv4LL Stack:/var/lib/avahi-autoipd:/sbin/nologin
18:postfix:x:89:89::/var/spool/postfix:/sbin/nologin
19:sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin
不区分大小写-i
将其中某一行改为大写
[root@localhost grep]# grep -n 'nologin' passwd
2:bin:x:1:1:bin:/bin:/sbin/nologin
3:daemon:x:2:2:daemon:/sbin:/sbin/nologin
4:adm:x:3:4:adm:/var/adm:/sbin/nologin
5:lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin
10:operator:x:11:0:operator:/root:/sbin/nologin
11:games:x:12:100:games:/usr/games:/sbin/nologin
12:ftp:x:14:50:FTP User:/var/ftp:/sbin/nologin
13:nobody:x:99:99:Nobody:/:/sbin/nologin
14:dbus:x:81:81:System message bus:/:/sbin/nologin
15:polkitd:x:999:998:User for polkitd:/:/sbin/nologin
16:avahi:x:70:70:Avahi mDNS/DNS-SD Stack:/var/run/avahi-daemon:/sbin/nologin
17:avahi-autoipd:x:170:170:Avahi IPv4LL Stack:/var/lib/avahi-autoipd:/sbin/nologin
18:postfix:x:89:89::/var/spool/postfix:/sbin/nologin
19:sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin
21:systemd-network:x:192:192:systemd Network Management:/:/sbin/nologin
22:php-fpm:x:1001:1001::/home/php-fpm:/sbin/nologin
23:apache:x:48:48:Apache:/usr/share/httpd:/sbin/nologin
[root@localhost grep]# grep -ni 'nologin' passwd
2:bin:x:1:1:bin:/bin:/sbin/nologin
3:daemon:x:2:2:daemon:/sbin:/sbin/nologin
4:adm:x:3:4:adm:/var/adm:/sbin/nologin
5:lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin
9:mail:x:8:12:mail:/var/spool/mail:/sbin/NOLogin
10:operator:x:11:0:operator:/root:/sbin/nologin
11:games:x:12:100:games:/usr/games:/sbin/nologin
12:ftp:x:14:50:FTP User:/var/ftp:/sbin/nologin
13:nobody:x:99:99:Nobody:/:/sbin/nologin
14:dbus:x:81:81:System message bus:/:/sbin/nologin
15:polkitd:x:999:998:User for polkitd:/:/sbin/nologin
16:avahi:x:70:70:Avahi mDNS/DNS-SD Stack:/var/run/avahi-daemon:/sbin/nologin
17:avahi-autoipd:x:170:170:Avahi IPv4LL Stack:/var/lib/avahi-autoipd:/sbin/nologin
18:postfix:x:89:89::/var/spool/postfix:/sbin/nologin
19:sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin
21:systemd-network:x:192:192:systemd Network Management:/:/sbin/nologin
22:php-fpm:x:1001:1001::/home/php-fpm:/sbin/nologin
23:apache:x:48:48:Apache:/usr/share/httpd:/sbin/nologin
可以发现第9行,以-i过滤是不区分大小写
取反-v
[root@localhost grep]# grep -v '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:1002:1002::/home/user1:/bin/bash
user2:x:1003:1003::/home/user2:/bin/bash
[root@localhost grep]# grep -inv '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
20:user1:x:1002:1002::/home/user1:/bin/bash
21:user2:x:1003:1003::/home/user2:/bin/bash
过滤出来后将剩余的行显示出来
递归遍历所有子目录-r
[root@localhost grep]# grep -r 'hello' /root/
/root/.bash_history:echo helloworld > 1.txt
/root/.bash_history:echo helloworld > 1.txt
/root/.bash_history:echo helloworld >> 1.txt
/root/.bash_history:echo helloworld 2> 1.txt
/root/.bash_history:hello=world
/root/.bash_history:echo $hello
/root/.bash_history:echo $hello
/root/.bash_history:echo $hello
/root/.bash_history:echo $hello
/root/.bash_history:export hello=world
/root/.bash_history:echo $hello
/root/.bash_history:echo $hello
/root/.bash_history:echo $hello
/root/.bash_history:unset hello
/root/.bash_history:echo $hello
/root/.bash_history:vi hello.sh
/root/.bash_history:chmod + x hello.sh
/root/.bash_history:chmod +x hello.sh
/root/.bash_history:sh hello.sh
/root/.bash_history:echo "helloworld" | tr '[hw]' '[HW]'
/root/.bash_history:echo "helloworld" | tr 'h' 'H'
/root/.bash_history:echo "helloworld" | tr '[a-z]' '[A-Z]'
/root/.bash_history:[ -d hello] || mkdir hello
/root/.bash_history:[ -d hello] || mkdir hello
/root/.bash_history:[ -d hello ] || mkdir hello
/root/.bash_history:[ -d hello ] && mkdir hello
/root/.bash_history:export hello=world
/root/.bash_history:echo $hello
/root/hello.sh:echo "hello!"
过滤出符合要求的行以及下面n行,-A+number
[root@localhost grep]# grep 'root' /etc/passwd
root:x:0:0:root:/root:/bin/bash
operator:x:11:0:operator:/root:/sbin/nologin
[root@localhost grep]# grep -A2 'root' /etc/passwd
root:x:0:0:root:/root:/bin/bash
bin:x:1:1:bin:/bin:/sbin/nologin
daemon:x:2:2:daemon:/sbin:/sbin/nologin
--
operator:x:11:0:operator:/root:/sbin/nologin
games:x:12:100:games:/usr/games:/sbin/nologin
ftp:x:14:50:FTP User:/var/ftp:/sbin/nologin
过滤出符合要求的行以及上面n行,-B+number
[root@localhost grep]# grep -B2 'root' /etc/passwd
root:x:0:0:root:/root:/bin/bash
--
halt:x:7:0:halt:/sbin:/sbin/halt
mail:x:8:12:mail:/var/spool/mail:/sbin/nologin
operator:x:11:0:operator:/root:/sbin/nologin
过滤出符合要求的行以及上下面n行,-C+number
[root@localhost grep]# grep -C2 'root' /etc/passwd
root:x:0:0:root:/root:/bin/bash
bin:x:1:1:bin:/bin:/sbin/nologin
daemon:x:2:2:daemon:/sbin:/sbin/nologin
--
halt:x:7:0:halt:/sbin:/sbin/halt
mail:x:8:12:mail:/var/spool/mail:/sbin/nologin
operator:x:11:0:operator:/root:/sbin/nologin
games:x:12:100:games:/usr/games:/sbin/nologin
ftp:x:14:50:FTP User:/var/ftp:/sbin/nologin
- 'string' 单引号 (single quote) 被单引号用括住的内容,将被视为单一字串。在引号内的代表变数的$符号,没有作用,也就是说,他被视为一般符号处理,防止任何变量替换。 heyyou=homeecho '$heyyou' # We get $heyyou
- "string" 双引号 (double quote) 被双引号用括住的内容,将被视为单一字串。它防止通配符扩展,但允许变量扩展。这点与单引数的处理方式不同。 heyyou=homeecho "$heyyou" # We get home
- `command` 倒引号 (backticks) 在前面的单双引号,括住的是字串,但如果该字串是一列命令列,会怎样?答案是不会执行。要处理这种情况,我们得用倒单引号来做。 fdv=`date +%F`echo "Today $fdv" 在倒引号内的 date +%F 会被视为指令,执行的结果会带入 fdv 变数中
[0-9]
[root@localhost grep]# grep '[0-9]' 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
operator:x:11:0:operator:/root:/sbin/nologin
games:x:12:100:games:/usr/games:/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
polkitd:x:999:998:User for polkitd:/:/sbin/nologin
avahi:x:70:70:Avahi mDNS/DNS-SD Stack:/var/run/avahi-daemon:/sbin/nologin
avahi-autoipd:x:170:170:Avahi IPv4LL Stack:/var/lib/avahi-autoipd:/sbin/nologin
postfix:x:89:89::/var/spool/postfix:/sbin/nologin
sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin
mysql:x:1000:1000::/home/mysql:/bin/bash
systemd-network:x:192:192:systemd Network Management:/:/sbin/nologin
php-fpm:x:1001:1001::/home/php-fpm:/sbin/nologin
apache:x:48:48:Apache:/usr/share/httpd:/sbin/nologin
[root@localhost grep]# grep -nv '[0-9]' /etc/inittab
1:# inittab is no longer used when using systemd.
2:#
3:# ADDING CONFIGURATION HERE WILL HAVE NO EFFECT ON YOUR SYSTEM.
4:#
5:# Ctrl-Alt-Delete is handled by /usr/lib/systemd/system/ctrl-alt-del.target
6:#
7:# systemd uses 'targets' instead of runlevels. By default, there are two main targets:
8:#
11:#
12:# To view current default target, run:
13:# systemctl get-default
14:#
15:# To set a default target, run:
16:# systemctl set-default TARGET.target
17:#
以任意字符开头^+str
[root@localhost grep]# cp /etc/inittab .
[root@localhost grep]# cat passwd >> inittab
[root@localhost grep]# grep -n '^#' inittab
1:# inittab is no longer used when using systemd.
2:#
3:# ADDING CONFIGURATION HERE WILL HAVE NO EFFECT ON YOUR SYSTEM.
4:#
5:# Ctrl-Alt-Delete is handled by /usr/lib/systemd/system/ctrl-alt-del.target
6:#
7:# systemd uses 'targets' instead of runlevels. By default, there are two main targets:
8:#
9:# multi-user.target: analogous to runlevel 3
10:# graphical.target: analogous to runlevel 5
11:#
12:# To view current default target, run:
13:# systemctl get-default
14:#
15:# To set a default target, run:
16:# systemctl set-default TARGET.target
17:#
[root@localhost grep]# grep -vn '^#' inittab
18:root:x:0:0:root:/root:/bin/bash
19:bin:x:1:1:bin:/bin:/sbin/nologin
20:daemon:x:2:2:daemon:/sbin:/sbin/nologin
21:adm:x:3:4:adm:/var/adm:/sbin/nologin
22:lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin
23:sync:x:5:0:sync:/sbin:/bin/sync
24:shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown
25:halt:x:7:0:halt:/sbin:/sbin/halt
26:mail:x:8:12:mail:/var/spool/mail:/sbin/NOLogin
27:operator:x:11:0:operator:/root:/sbin/nologin
28:games:x:12:100:games:/usr/games:/sbin/nologin
29:ftp:x:14:50:FTP User:/var/ftp:/sbin/nologin
30:nobody:x:99:99:Nobody:/:/sbin/nologin
31:dbus:x:81:81:System message bus:/:/sbin/nologin
32:polkitd:x:999:998:User for polkitd:/:/sbin/nologin
33:avahi:x:70:70:Avahi mDNS/DNS-SD Stack:/var/run/avahi-daemon:/sbin/nologin
34:avahi-autoipd:x:170:170:Avahi IPv4LL Stack:/var/lib/avahi-autoipd:/sbin/nologin
35:postfix:x:89:89::/var/spool/postfix:/sbin/nologin
36:sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin
37:mysql:x:1000:1000::/home/mysql:/bin/bash
38:systemd-network:x:192:192:systemd Network Management:/:/sbin/nologin
39:php-fpm:x:1001:1001::/home/php-fpm:/sbin/nologin
40:apache:x:48:48:Apache:/usr/share/httpd:/sbin/nologin
[root@localhost grep]# grep -vn '^#' inittab | grep -v '^3'
18:root:x:0:0:root:/root:/bin/bash
19:bin:x:1:1:bin:/bin:/sbin/nologin
20:daemon:x:2:2:daemon:/sbin:/sbin/nologin
21:adm:x:3:4:adm:/var/adm:/sbin/nologin
22:lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin
23:sync:x:5:0:sync:/sbin:/bin/sync
24:shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown
25:halt:x:7:0:halt:/sbin:/sbin/halt
26:mail:x:8:12:mail:/var/spool/mail:/sbin/NOLogin
27:operator:x:11:0:operator:/root:/sbin/nologin
28:games:x:12:100:games:/usr/games:/sbin/nologin
29:ftp:x:14:50:FTP User:/var/ftp:/sbin/nologin
40:apache:x:48:48:Apache:/usr/share/httpd:/sbin/nologin
[root@localhost grep]# grep -vn '^#' inittab | grep -v '^[1-3]'
40:apache:x:48:48:Apache:/usr/share/httpd:/sbin/nologin
[]非0-9
[root@localhost grep]# grep '[0-9]' inittab
# multi-user.target: analogous to runlevel 3
# graphical.target: analogous to runlevel 5
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
operator:x:11:0:operator:/root:/sbin/nologin
games:x:12:100:games:/usr/games:/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
polkitd:x:999:998:User for polkitd:/:/sbin/nologin
avahi:x:70:70:Avahi mDNS/DNS-SD Stack:/var/run/avahi-daemon:/sbin/nologin
avahi-autoipd:x:170:170:Avahi IPv4LL Stack:/var/lib/avahi-autoipd:/sbin/nologin
postfix:x:89:89::/var/spool/postfix:/sbin/nologin
sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin
mysql:x:1000:1000::/home/mysql:/bin/bash
systemd-network:x:192:192:systemd Network Management:/:/sbin/nologin
php-fpm:x:1001:1001::/home/php-fpm:/sbin/nologin
apache:x:48:48:Apache:/usr/share/httpd:/sbin/nologin
[root@localhost grep]# grep '[^0-9]' inittab
# inittab is no longer used when using systemd.
#
# ADDING CONFIGURATION HERE WILL HAVE NO EFFECT ON YOUR SYSTEM.
#
# Ctrl-Alt-Delete is handled by /usr/lib/systemd/system/ctrl-alt-del.target
#
# systemd uses 'targets' instead of runlevels. By default, there are two main targets:
#
# multi-user.target: analogous to runlevel 3
# graphical.target: analogous to runlevel 5
#
# To view current default target, run:
# systemctl get-default
#
# To set a default target, run:
# systemctl set-default TARGET.target
#
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
operator:x:11:0:operator:/root:/sbin/nologin
games:x:12:100:games:/usr/games:/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
polkitd:x:999:998:User for polkitd:/:/sbin/nologin
avahi:x:70:70:Avahi mDNS/DNS-SD Stack:/var/run/avahi-daemon:/sbin/nologin
avahi-autoipd:x:170:170:Avahi IPv4LL Stack:/var/lib/avahi-autoipd:/sbin/nologin
postfix:x:89:89::/var/spool/postfix:/sbin/nologin
sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin
mysql:x:1000:1000::/home/mysql:/bin/bash
systemd-network:x:192:192:systemd Network Management:/:/sbin/nologin
php-fpm:x:1001:1001::/home/php-fpm:/sbin/nologin
apache:x:48:48:Apache:/usr/share/httpd:/sbin/nologin
可以看到非0-9以外的字符都呈红色
[root@localhost grep]# grep '^[^0-9]' inittab
# inittab is no longer used when using systemd.
#
# ADDING CONFIGURATION HERE WILL HAVE NO EFFECT ON YOUR SYSTEM.
#
# Ctrl-Alt-Delete is handled by /usr/lib/systemd/system/ctrl-alt-del.target
#
# systemd uses 'targets' instead of runlevels. By default, there are two main targets:
#
# multi-user.target: analogous to runlevel 3
# graphical.target: analogous to runlevel 5
#
# To view current default target, run:
# systemctl get-default
#
# To set a default target, run:
# systemctl set-default TARGET.target
#
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
operator:x:11:0:operator:/root:/sbin/nologin
games:x:12:100:games:/usr/games:/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
polkitd:x:999:998:User for polkitd:/:/sbin/nologin
avahi:x:70:70:Avahi mDNS/DNS-SD Stack:/var/run/avahi-daemon:/sbin/nologin
avahi-autoipd:x:170:170:Avahi IPv4LL Stack:/var/lib/avahi-autoipd:/sbin/nologin
postfix:x:89:89::/var/spool/postfix:/sbin/nologin
sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin
mysql:x:1000:1000::/home/mysql:/bin/bash
systemd-network:x:192:192:systemd Network Management:/:/sbin/nologin
php-fpm:x:1001:1001::/home/php-fpm:/sbin/nologin
apache:x:48:48:Apache:/usr/share/httpd:/sbin/nologin
以非0-9的任意字符开头
[a-zA-Z]
[root@localhost grep]# grep '^[^a-zA-Z]' inittab
# inittab is no longer used when using systemd.
#
# ADDING CONFIGURATION HERE WILL HAVE NO EFFECT ON YOUR SYSTEM.
#
# Ctrl-Alt-Delete is handled by /usr/lib/systemd/system/ctrl-alt-del.target
#
# systemd uses 'targets' instead of runlevels. By default, there are two main targets:
#
# multi-user.target: analogous to runlevel 3
# graphical.target: analogous to runlevel 5
#
# To view current default target, run:
# systemctl get-default
#
# To set a default target, run:
# systemctl set-default TARGET.target
#
.任意一个字符
[root@localhost grep]# grep 'r.o' inittab
root:x:0:0:root:/root:/bin/bash
operator:x:11:0:operator:/root:/sbin/nologin
[root@localhost grep]# grep 'r..t' inittab
# Ctrl-Alt-Delete is handled by /usr/lib/systemd/system/ctrl-alt-del.target
# systemd uses 'targets' instead of runlevels. By default, there are two main targets:
# multi-user.target: analogous to runlevel 3
# graphical.target: analogous to runlevel 5
# To view current default target, run:
# To set a default target, run:
# systemctl set-default TARGET.target
root:x:0:0:root:/root:/bin/bash
operator:x:11:0:operator:/root:/sbin/nologin
ftp:x:14:50:FTP User:/var/ftp:/sbin/nologin
[root@localhost grep]# grep '/./' inittab
nobody:x:99:99:Nobody:/:/sbin/nologin
dbus:x:81:81:System message bus:/:/sbin/nologin
polkitd:x:999:998:User for polkitd:/:/sbin/nologin
systemd-network:x:192:192:systemd Network Management:/:/sbin/nologin
[root@localhost grep]# grep '/../' inittab
[root@localhost grep]# grep '/.../' inittab
# Ctrl-Alt-Delete is handled by /usr/lib/systemd/system/ctrl-alt-del.target
root:x:0:0:root:/root:/bin/bash
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
mail:x:8:12:mail:/var/spool/mail:/sbin/NOLogin
games:x:12:100:games:/usr/games:/sbin/nologin
ftp:x:14:50:FTP User:/var/ftp:/sbin/nologin
avahi:x:70:70:Avahi mDNS/DNS-SD Stack:/var/run/avahi-daemon:/sbin/nologin
avahi-autoipd:x:170:170:Avahi IPv4LL Stack:/var/lib/avahi-autoipd:/sbin/nologin
postfix:x:89:89::/var/spool/postfix:/sbin/nologin
sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin
mysql:x:1000:1000::/home/mysql:/bin/bash
apache:x:48:48:Apache:/usr/share/httpd:/sbin/nologin
*零个或多个
[root@localhost grep]# grep 'ro*' inittab
# inittab is no longer used when using systemd.
# Ctrl-Alt-Delete is handled by /usr/lib/systemd/system/ctrl-alt-del.target
# systemd uses 'targets' instead of runlevels. By default, there are two main targets:
# multi-user.target: analogous to runlevel 3
# graphical.target: analogous to runlevel 5
# To view current default target, run:
# To set a default target, run:
# systemctl set-default TARGET.target
root:x:0:0:root:/root:/bin/bash
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
operator:x:11:0:operator:/root:/sbin/nologin
games:x:12:100:games:/usr/games:/sbin/nologin
ftp:x:14:50:FTP User:/var/ftp:/sbin/nologin
polkitd:x:999:998:User for polkitd:/:/sbin/nologin
avahi:x:70:70:Avahi mDNS/DNS-SD Stack:/var/run/avahi-daemon:/sbin/nologin
avahi-autoipd:x:170:170:Avahi IPv4LL Stack:/var/lib/avahi-autoipd:/sbin/nologin
postfix:x:89:89::/var/spool/postfix:/sbin/nologin
sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin
systemd-network:x:192:192:systemd Network Management:/:/sbin/nologin
apache:x:48:48:Apache:/usr/share/httpd:/sbin/nologin
[root@localhost grep]# grep 'roo*' inittab
root:x:0:0:root:/root:/bin/bash
operator:x:11:0:operator:/root:/sbin/nologin
.*任意字符
[root@localhost grep]# grep '.*' inittab
# inittab is no longer used when using systemd.
#
# ADDING CONFIGURATION HERE WILL HAVE NO EFFECT ON YOUR SYSTEM.
#
# Ctrl-Alt-Delete is handled by /usr/lib/systemd/system/ctrl-alt-del.target
#
# systemd uses 'targets' instead of runlevels. By default, there are two main targets:
#
# multi-user.target: analogous to runlevel 3
# graphical.target: analogous to runlevel 5
#
# To view current default target, run:
# systemctl get-default
#
# To set a default target, run:
# systemctl set-default TARGET.target
#
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
operator:x:11:0:operator:/root:/sbin/nologin
games:x:12:100:games:/usr/games:/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
polkitd:x:999:998:User for polkitd:/:/sbin/nologin
avahi:x:70:70:Avahi mDNS/DNS-SD Stack:/var/run/avahi-daemon:/sbin/nologin
avahi-autoipd:x:170:170:Avahi IPv4LL Stack:/var/lib/avahi-autoipd:/sbin/nologin
postfix:x:89:89::/var/spool/postfix:/sbin/nologin
sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin
mysql:x:1000:1000::/home/mysql:/bin/bash
systemd-network:x:192:192:systemd Network Management:/:/sbin/nologin
php-fpm:x:1001:1001::/home/php-fpm:/sbin/nologin
apache:x:48:48:Apache:/usr/share/httpd:/sbin/nologin
[root@localhost grep]# grep 'mysql.*bash' inittab
mysql:x:1000:1000::/home/mysql:/bin/bash
[root@localhost grep]# grep 'mysql.*' inittab
mysql:x:1000:1000::/home/mysql:/bin/bash
str+{number}匹配str重复的次数
[root@localhost grep]# grep 'o{2}' inittab
[root@localhost grep]# grep 'o\{2\}' inittab
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
operator:x:11:0:operator:/root:/sbin/nologin
postfix:x:89:89::/var/spool/postfix:/sbin/nologin
若重复的次数为oooo也能匹配出来
str+{number,number}匹配范围
[root@localhost grep]# grep '9\{1,3\}' inittab
nobody:x:99:99:Nobody:/:/sbin/nologin
polkitd:x:999:998:User for polkitd:/:/sbin/nologin
postfix:x:89:89::/var/spool/postfix:/sbin/nologin
systemd-network:x:192:192:systemd Network Management:/:/sbin/nologin
egrep扩展
[root@localhost grep]# egrep '9{1,3}' inittab
nobody:x:99:99:Nobody:/:/sbin/nologin
polkitd:x:999:998:User for polkitd:/:/sbin/nologin
postfix:x:89:89::/var/spool/postfix:/sbin/nologin
systemd-network:x:192:192:systemd Network Management:/:/sbin/nologin
不需要反斜杠
-E同上
[root@localhost grep]# grep -E '9{1,3}' inittab
nobody:x:99:99:Nobody:/:/sbin/nologin
polkitd:x:999:998:User for polkitd:/:/sbin/nologin
postfix:x:89:89::/var/spool/postfix:/sbin/nologin
systemd-network:x:192:192:systemd Network Management:/:/sbin/nologin
(str){number,number}
[root@localhost grep]# grep -E '(99){1,3}' inittab
nobody:x:99:99:Nobody:/:/sbin/nologin
polkitd:x:999:998:User for polkitd:/:/sbin/nologin
str+匹配一次或多次str
[root@localhost grep]# grep 'o\+b' inittab
nobody:x:99:99:Nobody:/:/sbin/nologin
[root@localhost grep]# grep 'o\+t' inittab
root:x:0:0:root:/root:/bin/bash
operator:x:11:0:operator:/root:/sbin/nologin
str?匹配零次或一次str
[root@localhost grep]#
[root@localhost grep]# grep 'o\?t' inittab
# inittab is no longer used when using systemd.
# Ctrl-Alt-Delete is handled by /usr/lib/systemd/system/ctrl-alt-del.target
# systemd uses 'targets' instead of runlevels. By default, there are two main targets:
# multi-user.target: analogous to runlevel 3
# graphical.target: analogous to runlevel 5
# To view current default target, run:
# systemctl get-default
# To set a default target, run:
# systemctl set-default TARGET.target
root:x:0:0:root:/root:/bin/bash
shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown
halt:x:7:0:halt:/sbin:/sbin/halt
operator:x:11:0:operator:/root:/sbin/nologin
ftp:x:14:50:FTP User:/var/ftp:/sbin/nologin
dbus:x:81:81:System message bus:/:/sbin/nologin
polkitd:x:999:998:User for polkitd:/:/sbin/nologin
avahi:x:70:70:Avahi mDNS/DNS-SD Stack:/var/run/avahi-daemon:/sbin/nologin
avahi-autoipd:x:170:170:Avahi IPv4LL Stack:/var/lib/avahi-autoipd:/sbin/nologin
postfix:x:89:89::/var/spool/postfix:/sbin/nologin
sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin
systemd-network:x:192:192:systemd Network Management:/:/sbin/nologin
apache:x:48:48:Apache:/usr/share/httpd:/sbin/nologin
[root@localhost grep]# grep '70\?:' inittab
lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin
halt:x:7:0:halt:/sbin:/sbin/halt
avahi:x:70:70:Avahi mDNS/DNS-SD Stack:/var/run/avahi-daemon:/sbin/nologin
avahi-autoipd:x:170:170:Avahi IPv4LL Stack:/var/lib/avahi-autoipd:/sbin/nologin
[root@localhost grep]# grep '70\?:A' inittab
avahi:x:70:70:Avahi mDNS/DNS-SD Stack:/var/run/avahi-daemon:/sbin/nologin
avahi-autoipd:x:170:170:Avahi IPv4LL Stack:/var/lib/avahi-autoipd:/sbin/nologin
str|str或者
[root@localhost grep]# grep 'root\|mysql' inittab
root:x:0:0:root:/root:/bin/bash
operator:x:11:0:operator:/root:/sbin/nologin
mysql:x:1000:1000::/home/mysql:/bin/bash
[root@localhost grep]# grep 'root\|mysql' inittab
root:x:0:0:root:/root:/bin/bash
operator:x:11:0:operator:/root:/sbin/nologin
mysql:x:1000:1000::/home/mysql:/bin/bash
[root@localhost grep]# grep 'root\|mysql\|nobody' inittab
root:x:0:0:root:/root:/bin/bash
operator:x:11:0:operator:/root:/sbin/nologin
nobody:x:99:99:Nobody:/:/sbin/nologin
mysql:x:1000:1000::/home/mysql:/bin/bash