Change just the date format

Shell Programming and Scripting
1

need some more help please

i have a large file and
i want to change just the date format
with awk or sed

from this

yyyy-mm-dd

 2016-04-15  8.30 
 2016-04-15  7.30 
 2016-04-13  7.30 
 2016-04-11  8.30 
 2016-04-11  7.30 
 2016-04-08  8.30 
 2016-04-08  7.30 
 2016-04-06  7.30 
 2016-04-04  8.30

to this

dd-mm-yyyy

15-04-2016  8.30
15-04-2016  7.30
13-04-2016  7.30
11-04-2016  8.30
11-04-2016  7.30
08-04-2016  8.30
08-04-2016  7.30
06-04-2016  7.30
04-04-2016  8.30

leaving the times as they are

thanks

2

try:

sed 's/\([0-9][0-9][0-9][0-9]\)-\([0-9][0-9]\)-\([0-9][0-9]\)/\3-\2-\1/' infile
2 Likes
3

@rdrtx1

works great :slight_smile:

thanks

4

Hi.

Using a utility from the package dateutils, dconv :

#!/usr/bin/env bash

# @(#) s1       Demonstrate date manipulation, format changes, dconv.

# Utility functions: print-as-echo, print-line-with-visual-space, debug.
# export PATH="/usr/local/bin:/usr/bin:/bin"
LC_ALL=C ; LANG=C ; export LC_ALL LANG
pe() { for _i;do printf "%s" "$_i";done; printf "\n"; }
pl() { pe;pe "-----" ;pe "$*"; }
db() { ( printf " db, ";for _i;do printf "%s" "$_i";done;printf "\n" ) >&2 ; }
db() { : ; }
C=$HOME/bin/context && [ -f $C ] && $C dateutils.dconv

FILE=${1-data1}

pl " Input data file $FILE:"
cat $FILE

pl " Expected output:"
cat expected-output.txt

# 2016-04-15  8.30 -> 15-04-2016  8.30
pl " Results:"
dateutils.dconv -S -i "%F" -f "%d-%m-%Y" < $FILE

exit 0

producing:

$ ./s1

Environment: LC_ALL = C, LANG = C
(Versions displayed with local utility "version")
OS, ker|rel, machine: Linux, 3.16.0-4-amd64, x86_64
Distribution        : Debian 8 (jessie) 
bash GNU bash 4.3.30
dateutils.dconv dconv 0.3.1

-----
 Input data file data1:
 2016-04-15  8.30 
 2016-04-15  7.30 
 2016-04-13  7.30 
 2016-04-11  8.30 
 2016-04-11  7.30 
 2016-04-08  8.30 
 2016-04-08  7.30 
 2016-04-06  7.30 
 2016-04-04  8.30

-----
 Expected output:
15-04-2016  8.30
15-04-2016  7.30
13-04-2016  7.30
11-04-2016  8.30
11-04-2016  7.30
08-04-2016  8.30
08-04-2016  7.30
06-04-2016  7.30
04-04-2016  8.30

-----
 Results:
 15-04-2016  8.30 
 15-04-2016  7.30 
 13-04-2016  7.30 
 11-04-2016  8.30 
 11-04-2016  7.30 
 08-04-2016  8.30 
 08-04-2016  7.30 
 06-04-2016  7.30 
 04-04-2016  8.30

The dateutils package can be found in repositories Debian, MacOS ("brew"), SuSE, etc., and also at dateutils (verified 2016.04.16)

Best wishes ... cheers, drl

1 Like
5

Hello bob123,

Could you please try following and let me know if this helps you on same.

awk '{split($1, A,"-");$1=A[3] "-" A[2]"-" A[1]}; 1'  Input_file

Output will be as follows.

15-04-2016 8.30
15-04-2016 7.30
13-04-2016 7.30
11-04-2016 8.30
11-04-2016 7.30
08-04-2016 8.30
08-04-2016 7.30
06-04-2016 7.30
04-04-2016 8.30

Thanks,
R. Singh

6

yes that works great as well
thank you :slight_smile: