AWK截取字符串

substr(s, a, b) 

多列文本中某一列合并成一行 

awk ‘{print $2}‘ user1.txt |tr "\n" ","

awk ‘{print $2}‘ user1.txt |sed ‘s/\n/,/g‘

awk ‘{print $2}‘ user1.txt |xargs

vi 删除某行到结尾

:n,.d

统计多少行

wc -l

 vi编辑16进制文件

:%!xxd 内容转换成16进制

:%!xxd -r 16进制回转

linux 实用命令