CentOS 7 - 三剑客

grep

# 与
grep China city.txt | grep Beijing
# 或
grep -E "Beijing|BEIJING|beijing" city.txt
# 非
grep -v China city.txt
# 不区分大小写
grep -i china city.txt
# 非空行和非#开头的行
grep -v -E "^$|^#" /etc/httpd/conf/httpd.conf
# 完全匹配
grep -Fx

sed

# 修改行内容（以SELINUXTYPE开头）
sed "/^SELINUX/c SELINUX=disabled" /etc/selinux/config
# -i 原文编辑
sed -i "/^SELINUX/c SELINUX=disabled" /etc/selinux/config

# 替换文字
[root@centos801 <sub>]# cat city.txt 
beijing beijing
shanghai
beijing
shenzhen
BEIJING
[root@centos801 </sub>]# sed "s/beijing/Beijing/" city.txt 
Beijing beijing
shanghai
Beijing
shenzhen
BEIJING
[root@centos801 ~]# sed "s/beijing/Beijing/g" city.txt 
Beijing Beijing
shanghai
Beijing
shenzhen
BEIJING

awk

查询僵尸进程
ps -A -o stat,ppid,pid,cmd,user | grep -e '^[Zz]' | awk -F" " '{print $2}'
或者
ps -A -o stat,ppid,pid,cmd,user | grep -e '^[Zz]' | awk '{print $2}'