LINUX教学:Linux文本处理工具作业

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

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

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 办法一：getent passwd |cut -d: -f1,3 |grep -v root |grep "\b[[:digit:]]\{1,3\}\b$"
2 办法二：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 办法一：cat /etc/rc.d/init.d/functions |grep -o "^.*[[:graph:]]()"
2 办法二：cat /etc/rc.d/init.d/functions |egrep "^.*[^[:space:]]\(\)"
3 办法三：cat /etc/rc.d/init.d/functions |egrep -o "^.*\>\(\)"

1 echo /etc/rc.d/init.d/functions | egrep -o "[^/]+/?$"

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

1 last |grep ^root |egrep -o "([0-9]{1,3}\.){3}[0-9]{1,3}" |sort |uniq -c

1  \b[0-9]\b                       0-9
2  \b[0-9]{2}\b                    10-99 
3  \b[1][0-9]{2}\b                 100-199
4  \b[2][0-4][0-9]\b               200-249
5  \b[2][5][0-5]\b                 250-255

1 ifconfig | egrep -o "\<(([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4]0-9]|25[0-5])\.){3}([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\>"

1 echo "welcome to magedu linux" |grep -o "." |sort |uniq -c |sort -nr