grep命令

语法：grep [-cinvABC] ‘word’ filename

• -c：打印符合要求的行数
• -i：不区分大小写
• -n：在输出符合要求的行的同时连同行号一起输出
• -v：打印不符合要求的行
• -r：遍历所有子目录
• -A：后跟一个数字（有无空格都可以），例如–A2则表示打印符合要求的行以及下面两行
• -B：后跟一个数字，例如–B2则表示打印符合要求的行以及上面两行
• -C：后跟一个数字，例如–C2则表示打印符合要求的行以及上下各两行

[root@centos-01 ~]# ls 1.txt 2.txt anaconda-ks.cfg test [root@centos-01 ~]# mkdir grep [root@centos-01 ~]# cd grep/ [root@centos-01 grep]# cp /etc/passwd . [root@centos-01 grep]# ls passwd [root@centos-01 grep]# pwd /root/grep [root@centos-01 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 systemd-network:x:192:192:systemd Network Management:/:/sbin/nologin dbus:x:81:81:System message bus:/:/sbin/nologin polkitd:x:999:997:User for polkitd:/:/sbin/nologin postfix:x:89:89::/var/spool/postfix:/sbin/nologin sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin chrony:x:998:996::/var/lib/chrony:/sbin/nologin [root@centos-01 grep]# which grep alias grep='grep --color=auto'/usr/bin/grep [root@centos-01 grep]# grep -c 'nologin' passwd 15 [root@centos-01 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:systemd-network:x:192:192:systemd Network Management:/:/sbin/nologin 15:dbus:x:81:81:System message bus:/:/sbin/nologin 16:polkitd:x:999:997:User for polkitd:/:/sbin/nologin 17:postfix:x:89:89::/var/spool/postfix:/sbin/nologin 18:sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin 19:chrony:x:998:996::/var/lib/chrony:/sbin/nologin

---

[root@centos-01 grep]# vim passwd

在文件最后添加

NOLogin

保存退出

---

[root@centos-01 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:systemd-network:x:192:192:systemd Network Management:/:/sbin/nologin 15:dbus:x:81:81:System message bus:/:/sbin/nologin 16:polkitd:x:999:997:User for polkitd:/:/sbin/nologin 17:postfix:x:89:89::/var/spool/postfix:/sbin/nologin 18:sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin 19:chrony:x:998:996::/var/lib/chrony:/sbin/nologin [root@centos-01 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:systemd-network:x:192:192:systemd Network Management:/:/sbin/nologin 15:dbus:x:81:81:System message bus:/:/sbin/nologin 16:polkitd:x:999:997:User for polkitd:/:/sbin/nologin 17:postfix:x:89:89::/var/spool/postfix:/sbin/nologin 18:sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin 19:chrony:x:998:996::/var/lib/chrony:/sbin/nologin 20:NOLogin [root@centos-01 grep]# grep -vni '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 [root@centos-01 grep]# grep -nA2 'root' passwd 1:root:x:0:0:root:/root:/bin/bash 2-bin:x:1:1:bin:/bin:/sbin/nologin 3-daemon:x:2:2:daemon:/sbin:/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 [root@centos-01 grep]# grep -nB2 'root' passwd 1:root:x:0:0:root:/root:/bin/bash -- 8-halt:x:7:0:halt:/sbin:/sbin/halt 9-mail:x:8:12:mail:/var/spool/mail:/sbin/nologin 10:operator:x:11:0:operator:/root:/sbin/nologin [root@centos-01 grep]# grep -nC2 'root' passwd 1:root:x:0:0:root:/root:/bin/bash 2-bin:x:1:1:bin:/bin:/sbin/nologin 3-daemon:x:2:2:daemon:/sbin:/sbin/nologin -- 8-halt:x:7:0:halt:/sbin:/sbin/halt 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 [root@centos-01 ~]# grep -n 'root' /etc/passwd 1:root:x:0:0:root:/root:/bin/bash 10:operator:x:11:0:operator:/root:/sbin/nologin [root@centos-01 ~]# grep -nv 'nologin' /etc/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 [root@centos-01 ~]# cd grep/ [root@centos-01 grep]# ls passwd [root@centos-01 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 systemd-network:x:192:192:systemd Network Management:/:/sbin/nologin dbus:x:81:81:System message bus:/:/sbin/nologin polkitd:x:999:997:User for polkitd:/:/sbin/nologin postfix:x:89:89::/var/spool/postfix:/sbin/nologin sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin chrony:x:998:996::/var/lib/chrony:/sbin/nologin [root@centos-01 grep]# grep -v '[0-9]' passwd NOLogin

• 在正则表达式中，“^”表示行的开始，“$”表示行的结尾，空行则可以用“^$”表示。

[root@centos-01 grep]# grep -n '^#' /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:# 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@centos-01 grep]# cp /etc/inittab ./ [root@centos-01 grep]# vim inittab

随便添加一行字符串

abcdefg

保存退出

[root@centos-01 grep]# grep -nv '^#' inittab 18:abcdefg

---

[root@centos-01 grep]# vim inittab

添加一行数字

12345

保存退出

[root@centos-01 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 # abcdefg

---

• .：表示任意一个字符
• *：表示零个或多个前面的字符
• .*：表示零个或多个任意字符，空行也包含在内

[root@centos-01 grep]# grep 'r.o' passwd root:x:0:0:root:/root:/bin/bash operator:x:11:0:operator:/root:/sbin/nologin [root@centos-01 grep]# grep 'oo*' 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 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 systemd-network:x:192:192:systemd Network Management:/:/sbin/nologin dbus:x:81:81:System message bus:/:/sbin/nologin polkitd:x:999:997:User for polkitd:/:/sbin/nologin postfix:x:89:89::/var/spool/postfix:/sbin/nologin sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin chrony:x:998:996::/var/lib/chrony:/sbin/nologin NOLogin [root@centos-01 grep]# grep '.*' 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 systemd-network:x:192:192:systemd Network Management:/:/sbin/nologin dbus:x:81:81:System message bus:/:/sbin/nologin polkitd:x:999:997:User for polkitd:/:/sbin/nologin postfix:x:89:89::/var/spool/postfix:/sbin/nologin sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin chrony:x:998:996::/var/lib/chrony:/sbin/nologin NOLogin [root@centos-01 grep]# grep 'sshd.*login' passwd sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin

• { }，其内部为数字，表示前面的字符要重复的次数。注意，{ }左右都需要加上脱义字符‘\’。另外，使用{ }还可以表示一个范围的，具体格式是‘{n1,n2}’，其中n1

[root@centos-01 grep]# 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 operator:x:11:0:operator:/root:/sbin/nologin postfix:x:89:89::/var/spool/postfix:/sbin/nologin [root@centos-01 grep]# grep 'o\{0,3\}' 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 systemd-network:x:192:192:systemd Network Management:/:/sbin/nologin dbus:x:81:81:System message bus:/:/sbin/nologin polkitd:x:999:997:User for polkitd:/:/sbin/nologin postfix:x:89:89::/var/spool/postfix:/sbin/nologin sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin chrony:x:998:996::/var/lib/chrony:/sbin/nologin NOLogin

• grep -E==egrep

[root@centos-01 grep]# grep -E '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 operator:x:11:0:operator:/root:/sbin/nologin postfix:x:89:89::/var/spool/postfix:/sbin/nologin

• +：表示一个或一个以上前面的字符

[root@centos-01 grep]# grep 'o\+o' 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 operator:x:11:0:operator:/root:/sbin/nologin postfix:x:89:89::/var/spool/postfix:/sbin/nologin

• ?：表示零个或一个前面的字符

[root@centos-01 grep]# grep 'i\?v' 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 ftp:x:14:50:FTP User:/var/ftp:/sbin/nologin postfix:x:89:89::/var/spool/postfix:/sbin/nologin sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin chrony:x:998:996::/var/lib/chrony:/sbin/nologin

• |：筛选字符串1或者字符串2

[root@centos-01 grep]# grep -E 'root|nologin' 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 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 systemd-network:x:192:192:systemd Network Management:/:/sbin/nologin dbus:x:81:81:System message bus:/:/sbin/nologin polkitd:x:999:997:User for polkitd:/:/sbin/nologin postfix:x:89:89::/var/spool/postfix:/sbin/nologin sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin chrony:x:998:996::/var/lib/chrony:/sbin/nologin

egrep命令

egrep是grep的扩展版本，可以用egrep完成grep不能完成的工作，grep能完成的egrep完全可以完成。

[root@centos-01 grep]# egrep '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 operator:x:11:0:operator:/root:/sbin/nologin postfix:x:89:89::/var/spool/postfix:/sbin/nologin [root@centos-01 grep]# egrep 'o+o' 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 operator:x:11:0:operator:/root:/sbin/nologin postfix:x:89:89::/var/spool/postfix:/sbin/nologin [root@centos-01 grep]# egrep 'o+l' 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 systemd-network:x:192:192:systemd Network Management:/:/sbin/nologin dbus:x:81:81:System message bus:/:/sbin/nologin polkitd:x:999:997:User for polkitd:/:/sbin/nologin postfix:x:89:89::/var/spool/postfix:/sbin/nologin sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin chrony:x:998:996::/var/lib/chrony:/sbin/nologin [root@centos-01 grep]# egrep 'f?or' passwd operator:x:11:0:operator:/root:/sbin/nologin systemd-network:x:192:192:systemd Network Management:/:/sbin/nologin polkitd:x:999:997:User for polkitd:/:/sbin/nologin

• ( )表示一个整体，例如(o){2}就表示‘oo’。

[root@centos-01 grep]# egrep '(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 operator:x:11:0:operator:/root:/sbin/nologin postfix:x:89:89::/var/spool/postfix:/sbin/nologin

转载于:https://www.cnblogs.com/Genesis2018/p/9079763.html

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