[DATE] Pattern matching notation

Shell Programming and Scripting
1

Hello,
I want to verify the format date like 2013-03-08 (YYYY-MM-DD)
It doesn't work because the pattern matching notation below returns false while the date is right.
Can you help me ? Thanks in advance

case "$6" in ([1-9][0-9][0-9][0-9]-0[1-9]-0[1-9] | [1-9][0-9][0-9][0-9]-1[0-2]-1[0-9] | [1-9][0-9][0-9][0-9]-1[0-2]-2[0-9] | [1-9][0-9][0-9][0-9]-1[0-2]-3[0-1]) 
# Nothing, OK ! 
    ;; 
(*)   echo 'Fatal, $6 eq '"'$6'"', Right format is YYYY-MM-DD' >&2 
    ;; 
esac
2

Even if you fix this pattern, I don't think it will be reliable because this will not cover conditions like leap year.

So If you have GNU date , you can simply do:

[[ "$( date -d "$1" +%F 2>&1 | grep invalid )" = "" ]] && echo "$1 is valid" || echo "$1 is invalid"
3

It's OK, I have forgotten some cases

case "$6" in
([1-9][0-9][0-9][0-9]-0[1-9]-0[1-9] | [1-9][0-9][0-9][0-9]-0[1-9]-1[0-9] | [1-9][0-9][0-9][0-9]-0[1-9]-2[0-9] | [1-9][0-9][0-9][0-9]-0[1-9]-3[0-1] | [1-9][0-9][0-9][0-9]-1[0-2]-0[1-9] | [1-9][0-9][0-9][0-9]-1[0-2]-1[0-9] | [1-9][0-9][0-9][0-9]-1[0-2]-2[0-9] | [1-9][0-9][0-9][0-9]-1[0-2]-3[0-1])
# nothing, OK !
  ;;
(*)
  echo 'Fatal, $6 = '"'$6'"', Date non conforme OU absente' >&2
  #exit 1
  ;;
esac

---------- Post updated at 02:13 AM ---------- Previous update was at 02:13 AM ----------

Thank you for this alternative :slight_smile:

4

I would like to simplify this pattern notation

([1-9][0-9][0-9][0-9]-0[1-9]-0[1-9] | [1-9][0-9][0-9][0-9]-0[1-9]-1[0-9] | [1-9][0-9][0-9][0-9]-0[1-9]-2[0-9] | [1-9][0-9][0-9][0-9]-0[1-9]-3[0-1] | [1-9][0-9][0-9][0-9]-1[0-2]-0[1-9] | [1-9][0-9][0-9][0-9]-1[0-2]-1[0-9] | [1-9][0-9][0-9][0-9]-1[0-2]-2[0-9] | [1-9][0-9][0-9][0-9]-1[0-2]-3[0-1])

with that

([1-9][0-9][0-9][0-9]-[0(1-9) | 1(0-2)]-[0(1-9) | 1(0-9) | 2(0-9) | 3(0-1)])

But it doesn't work.

Is this notation

 [0(1-9) | 1(0-2)]

means
(01 10) (01 11) (01 12)....(09 10) (09 11) (09 12)....(09 12)

Thank you

---------- Post updated 11-03-13 at 01:13 AM ---------- Previous update was 10-03-13 at 04:14 AM ----------

Hello,
Can anyone help me ?
I wanted to simplfy this first pattern with the second, but it doesn't work.

([1-9][0-9][0-9][0-9]-0[1-9]-0[1-9] | [1-9][0-9][0-9][0-9]-0[1-9]-1[0-9] | [1-9][0-9][0-9][0-9]-0[1-9]-2[0-9] | [1-9][0-9][0-9][0-9]-0[1-9]-3[0-1] | [1-9][0-9][0-9][0-9]-1[0-2]-0[1-9] | [1-9][0-9][0-9][0-9]-1[0-2]-1[0-9] | [1-9][0-9][0-9][0-9]-1[0-2]-2[0-9] | [1-9][0-9][0-9][0-9]-1[0-2]-3[0-1])

([1-9][0-9][0-9][0-9]-[0(1-9) | 1(0-2)]-[0(1-9) | 1(0-9) | 2(0-9) | 3(0-1)])

Thanks in advance

5

How about perl

 
#!/usr/bin/perl

use strict;
use Time::Local;
my $dt="2013-12-01";
my ($year,$month,$date)=unpack("A4 x1 A2 x1 A2",$dt);
eval  {
        timelocal(0,0,0,$date,$month-1,$year-1900);
        print "Correct date\n";
} or die "Date is not correct $@\n";