awk 如何格式化某列时间串

cuiyubing819

awk  -F "," '{print strftime("%Y%m%d", $4) }' txt
19700101
19700101
19700101
19700101
19700101
19700101
$ cat txt
"0553","551","","1999/12/21","2999/12/20 23:59:59",""
"0564","551","","1999/12/21","2999/12/20 23:59:59",""
"0556","551","","2999/12/21","2999/12/20 23:59:59",""
"0563","551","","1999/12/21","1994/12/20 23:59:59",""
"0562","551","ͭ"1999/12/21","2999/12/20 23:59:59",""
"0552","551","","1999/12/21","1999/12/20 23:59:59",""
$
我想格式化输出第4列 为什么上面输出为19700101，
如何打印系统时间大于第四列的时间串的行数据呢？
哪位大佬帮忙解答下谢谢

vagrant_1220

awk -F ',' '{cmd="date -d "$4" \"+%Y%m%d\"";cmd|getline dt;print dt;close(cmd)}' txt  ；你代码中strftime 第二个参数 $4 应该是时间戳格式，所以你的输出为19700101

wh7211

回复 1# cuiyubing819

我想格式化输出第4列 为什么上面输出为19700101，

1. awk -F"," '{split($4,a,"[\"/]");print a[2]a[3]a[4]}' txt
   
2. awk -F"," '{split($4,a,"[\"/]");b=mktime(""a[2]" "a[3]" "a[4]" 00 00 00");print strftime("%Y%m%d",b)}' txt

复制代码

如何打印系统时间大于第四列的时间串的行数据呢？

1. awk -F"," '{split($4,a,"[\"/]");b=mktime(""a[2]" "a[3]" "a[4]" 00 00 00")}systime()>b' txt

复制代码

cuiyubing819

wh7211 发表于 2018-10-30 18:08
回复 1# cuiyubing819

祝您生活愉快，谢谢大佬

cuiyubing819

vagrant_1220 发表于 2018-10-30 17:54
awk -F ',' '{cmd="date -d "$4" \"+%Y%m%d\"";cmd|getline dt;print dt;close(cmd)}' txt  ；你代码中strf ...

感谢大佬讲解，祝您生活愉快

cuiyubing819

回复 2# vagrant_1220

$ awk -F ',' '{cmd="date -d "$4" \"+%Y%m%d\"";cmd|getline dt;print dt}' txt
19991221
19991221
29991221
29991221
29991220
29991220
$ awk -F ',' '{cmd="date -d "$4" \"+%Y%m%d\"";cmd|getline dt;print dt;close(cmd)}' txt
19991221
19991221
29991221
19991221
29991220
19991221

大佬加close 和不加close的区别为啥这么大，是不是 必须和getline配合用吗

cuiyubing819

回复 2# vagrant_1220

$ awk -F ',' '{cmd="date -d "$4" \"+%Y%m%d\"";cmd|getline dt;print dt}' txt
19991221
19991221
29991221
29991221
29991220
29991220
$ awk -F ',' '{cmd="date -d "$4" \"+%Y%m%d\"";cmd|getline dt;print dt;close(cmd)}' txt
19991221
19991221
29991221
19991221
29991220
19991221

大佬加close 和不加close的区别为啥这么大，是不是 必须和getline

cuiyubing819

回复 2# vagrant_1220

awk -F ',' '{cmd="date -d "$4" \"+%Y%m%d\"";cmd|getline dt;print dt}' txt
19991221
19991221
29991221
29991221
29991220
29991220
awk -F ',' '{cmd="date -d "$4" \"+%Y%m%d\"";cmd|getline dt;print dt;close(cmd)}' txt
19991221
19991221
29991221
19991221
29991220
19991221

大佬加close 和不加close的区别为啥这么大，是不是 必须和getline

cuiyubing819

回复 3# wh7211

$ cat txt
"0553","551","","1999/12/21","2999/12/20 23:59:59",""
"0564","551","","1999/12/21","2999/12/20 23:59:59",""
"0556","551","","2999/12/21","2999/12/20 23:59:59",""
"0563","551","","1999/12/21","1994/12/20 23:59:59",""
"0562","551","ͭ"1999/12/21","2999/12/20 23:59:59",""
"0552","551","","1999/12/21","1999/12/20 23:59:59",""
大佬来个组合的系统时间判断，
我的最终需求是
打印第四列小于系统时间，第5列大于系统时间的行数据，
谢谢大佬回复

vagrant_1220

awk中的close()指令, 语法有两种, close( filename ) 和close( 置于pipe之前的command )，awk中打开文件或使用pipe,close是必不可少的，否则可能出现文件句柄泄露或从管道拿到的都是之前命令的数据，就如你遇到的情况。