Hello Sed/Bash/Awk experts,
I have a file full of dates in the following format:
Feb 5 2015 Nov 25 2014 Apr 16 2015 What I would like is to convert them to this format:
YYYY-MM-DD So they should look like this:
2015-02-05 2014-11-25 2015-04-16 Thanks for your help.
You can simply use:
date -f dates.txt +%Y-%m-%d In the -f option you can provide your input file with one date per line.
-f - that's an eye-opener!
date to handle the case where you have a file of just dates, nothing else. I guess it happens given this question though!Using awk
awk 'BEGIN{x=" JANFEBMARAPRMAYJUNJULAUGSEPOCTNOVDEC"} {printf "%04d-%02d-%02d\n",$3,index(x,toupper($1))/3,$2}' file 
the date command is your friend here:
date --date="Feb 5 2015" +"%Y-%m-%d" 2015-02-05 so, you can say:
$ cat my_file | while read -r dt > do > date --date="${dt}" +"%Y-%m-%d" > done 2015-02-05 2014-11-25 2015-04-16 
IFS= to prevent word splitting and see unix.stackexchange.com/q/169716/133219 for why using a shell loop just to manipulate text is to be avoided.paste the following:
{ month="00"; mon=toupper($1); if(mon=="JAN") month="01"; else if(mon=="FEB") month="02"; else if(mon=="MAR") month="03"; else if(mon=="APR") month="04"; else if(mon=="MAY") month="05"; else if(mon=="JUN") month="06"; else if(mon=="JUL") month="07"; else if(mon=="AUG") month="08"; else if(mon=="SEP") month="09"; else if(mon=="OCT") month="10"; else if(mon=="NOV") month="11"; else if(mon=="DEC") month="12"; printf("%s-%s-%02d\n", $3, month, $2) } into a file (We'll refer to the filename as [script_filename] execute the following: awk -F' ' -E [script_filename] [date_filename] Where [date_filename] refers to the file which contains the dates you wish to convert.
-E, thanks! Working on OS X as well. Personally, I still wouldn't set FS, although I certainly see your point.-E so I just googled it and apparently it's like -f but it disallows other normal awk functionality like assigning variables in the file list. While useful in CGI scripts apparently, -f is the normal way to introduce a script file in all awks. You need to make the 2nd %d in your printf either %s or %2d so the singe digit month numbers are printed as 2 digits.