文本处理器 grep/awk/sed
grep:文本过滤器
grep ‘pattern’ input_file …
sed:流编辑器
awk:报告生成器
格式化后显示
a.k.a Aho, Kernighan and Weinberger
默认使用空格作为分隔符
new awk: nawk
# awk [options] ‘script’ file1 file2 …
示例:
awk ‘{print $1,$4}’ t.txt # 只打印2个列
awk ‘BEGIN{OFS=”:”}{print $1,$2,$3}’ t.txt # 换分隔符
awk的输出:
awk ‘BEGIN{OFS=”:”}{print $1,$2,$3,”bill”}’ t.txt # 插入自定义输出
awk -F: ‘/^r*/{print $3}’ /etc/passwd # 以r起始的
awk -F: ‘$3>=500{print $1,$3}’ /etc/passwd
awk -F: ‘$3-4000>=500{print $1,$3}’ /etc/passwd
awk -F: ‘$7~”bash$”{print $3,$1,$7}’ /etc/passwd # 以bash结尾的
awk -F: ‘$7!~”bash$”{print $3,$1,$7}’ /etc/passwd # 和上面取反
awk -F: ‘$3==0,$7~”bash”{print $1,$3,$7}’ /etc/passwd
awk -F: ‘$3==0,$7~”nologin”{printf “%10s%10s%20s\n”,$1,$3,$7}’ /etc/passwd # 多个逻辑条件是||的关系
awk -F: ‘BEGIN{print “Username Id Shell”}$3==0,$7~”nologin”{printf “%10s%10s%20s\n”,$1,$3,$7}’ /etc/passwd #上面的基础上利用BEGIN打印表头
awk -F: ‘BEGIN{print “Username Id Shell”}$3==0,$7~”nologin”{printf “%10s%10s%20s\n”,$1,$3,$7}END{print “process finsh!”}’ /etc/passwd # 在上面的基础上(END)打印表尾
awk -F: ‘{if ($1==”root”)print $1,”Admin”;else print $1,”Common User”}’ /etc/passwd
![](http://www.billstudy.com/wp-content/uploads/2016/01/wpid-ed2bbe325447efb428b0137f688a467e_7cdfed79-e906-4189-974a-7314fb32757e.jpg)
![](http://www.billstudy.com/wp-content/uploads/2016/01/wpid-ed2bbe325447efb428b0137f688a467e_12ff1db5-c767-4322-ad45-484499049a26.jpg)
![](http://www.billstudy.com/wp-content/uploads/2016/01/wpid-ed2bbe325447efb428b0137f688a467e_07bfa5b0-c1ce-439d-a55b-06405b49d3f2.jpg)
![](http://www.billstudy.com/wp-content/uploads/2016/01/wpid-ed2bbe325447efb428b0137f688a467e_2b031511-84e9-4731-bbc3-ec074774a5ac.jpg)
![](http://www.billstudy.com/wp-content/uploads/2016/01/wpid-ed2bbe325447efb428b0137f688a467e_3f7d6f9e-1ed8-4034-b489-c76386d1c059.jpg)
![](http://www.billstudy.com/wp-content/uploads/2016/01/wpid-ed2bbe325447efb428b0137f688a467e_18193ad3-527c-4aa4-9c2a-678db9426cab.jpg)
![](http://www.billstudy.com/wp-content/uploads/2016/01/wpid-ed2bbe325447efb428b0137f688a467e_5b822050-4f74-4b68-a251-c3b6cff929fc.jpg)
![](http://www.billstudy.com/wp-content/uploads/2016/01/wpid-ed2bbe325447efb428b0137f688a467e_d6aacddf-8395-40a3-8422-e645fd922b3d.jpg)