'awk command to change date format

I have a file that contains the below records:

**cat Date.txt**
SEPT,30-SEP-2017
MARCH,30-MAR-2018
JULY,30-JUL-2017
DECEM,30-DEC-2017
AUGS,30-AUG-2017

I want the output to be:

    SEPT,20170930
    MARCH,20180330
    JULY,20170730
    DECEM,20171230
    AUGS,20170830

I have done a script with a while loop, as given below.

    cat Date.txt > /tmp/exp.part
    while read line
    do
    Dat=$(echo $line | awk -F , '{print $1}')
    DatNew=$(date -d $Exp +%Y%m%d)
    echo $DatNew
    done < /tmp/exp.part

I want to know if I can do it from the awk command, instead of writing a while loop.

shell


Solution 1:[1]

One way using system command within awk: Input file:

$ cat file
27-SEP-2017
28-MAR-2018
27-JUL-2017
27-DEC-2017
29-AUG-2017


$ awk '{system("date -d " $0 " +%Y%m%d")}' file
20170927
20180328
20170727
20171227
20170829

For the updated input file:

$ cat file
SEP,27-SEP-2017
MAR,28-MAR-2018
JUL,27-JUL-2017
DEC,27-DEC-2017
AUG,29-AUG-2017


$ awk -F, '{system("date -d " $2 " +%Y%m%d")}' file
20170927
20180328
20170727
20171227
20170829

For the updated requirement:

$ cat file
SEPT,30-SEP-2017
MARCH,30-MAR-2018
JULY,30-JUL-2017
DECEM,30-DEC-2017
AUGS,30-AUG-2017

$ awk -F, '{cmd="date -d "q $2 q" "s"+%Y%m%d"s; cmd|getline x;print $1,x}'  dq='"' sq="'"  OFS=, file
SEPT,20170930
MARCH,20180330
JULY,20170730
DECEM,20171230
AUGS,20170830

Solution 2:[2]

Following on Guru's answer, this also seemed to work:

$ awk -F, '{cmd="date -d "$2" +%Y%m%d"; cmd|getline x;print $1,x}' OFS=',' file
SEPT,20170930
MARCH,20180330
JULY,20170730
DECEM,20171230
AUGS,20170830

Note the awk version was actually mawk:

$ awk -W version
mawk 1.3.3 Nov 1996, Copyright (C) Michael D. Brennan

Sources

This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.

Source: Stack Overflow

Solution Source
Solution 1
Solution 2 alan

Related Questions