文本处理工具作业

1 方法一：cat /proc/meminfo |grep -i ^s
2 方法二：cat /proc/meminfo |grep ^[sS]

1 cat /etc/passwd | grep -v /bin/bash

1 方法一：cat /etc/passwd |grep "^rpc\b" |cut -d: -f7
2 方法二：getent passwd rpc |cut -d: -f7

1 cat /etc/passwd |grep "\b[0-9]\{2,3\}\b"

1 cat /etc/grub2.cfg |egrep "^[[:space:]]+[[:graph:]].*"

1 netstat -tan |grep "LISTEN[[:space:]]\+$"

1 方法一：getent passwd |cut -d: -f1,3 |grep -v root |grep "\b[[:digit:]]\{1,3\}\b$"
2 方法二：getent passwd |cut -d: -f1,3 |grep -ve root -e "\b[[:digit:]]\{4,\}\b"

1 cat /etc/passwd |grep -o "^\(.\+\b\).*\b\1$"

1 df |grep sd |grep -Eo "[0-9]{1,3}%" |sort -nr

1 cat /etc/passwd |egrep "^(root|mage|wang)\b" |cut -d: -f3,7

1 cat /etc/rc.d/init.d/functions |egrep "^[[:alpha:]](.*|_)+\(\)"

1 方法一：echo /etc/rc.d/init.d/functions | egrep -o "[[:alpha:]]*$"
2 方法二：echo /etc/rc.d/init.d/functions | egrep -o "[^/]+/?$"

1 方法一：echo /etc/rc.d/init.d/functions | egrep -o "(/).*\1"
2 方法二：echo /etc/rc.d/init.d/functions | egrep -o "^/.*/\b"

1 方法一：last |grep ^root |tr -s ‘ ‘ |cut -d ‘ ‘ -f3 |grep ^[0-9] |sort |uniq -c
2 方法二：last |grep ^root |egrep -o "([0-9]{1,3}\.){3}[0-9]{1,3}" |sort |uniq -c

1 echo {0..1000} |egrep -o "\b[0-9]\b"                     0-9
2 echo {0..1000} |egrep -o "\b[0-9]{2}\b"                  10-99 
3 echo {0..1000} |egrep -o "\b[1][0-9]{2}\b"               100-199
4 echo {0..1000} |egrep -o "\b[2][0-4][0-9]\b"             200-249
5 echo {0..1000} |egrep -o "\b[2][5][0-5]\b"               250-255

1 ifconfig |grep netmask |tr -s ‘ ‘|cut -d ‘ ‘ -f3

1 echo "welcome to magedu linux" |tr -d ‘ ‘ |grep -o "." |sort |uniq -c |sort -nr |tr -s " " |cut -d " " -f3 |tr "\n" " ";echo