Increment date in shell script on AIX [duplicate] - perl

Question

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What is the optimal way to loop between two dates in Perl?
(5 answers)
Closed 6 years ago.
I have to create a shell script file that accepts a string, start date and end date and generates the output file in the below format.
Note : Dates are in MM/DD/YYYY
string,start date
string,start date + 1
...
string,end date
I am not able to increment the date. I tried using date -d option but it is not available on AIX.
Could someone please help with a built in shell script command or perl command to increment the date ?.

Answer 1

Given a constraint of 'uses core':
#!/usr/bin/env perl
use strict;
use warnings;
use Time::Piece;
use Time::Seconds;
my $FORMAT = '%m/%d/%Y';
my $start = '01/22/2016';
my $end = '01/31/2016';
my $start_t = Time::Piece->strptime( $start, $FORMAT );
my $end_t = Time::Piece->strptime( $end, $FORMAT );
while ( $start_t <= $end_t ) {
print $start_t ->strftime($FORMAT), "\n";
$start_t += ONE_DAY;
}
Both Time::Piece and Time::Seconds are core as of perl 5.9.5. The latter is only needed for ONE_DAY - otherwise you can just add 60 * 60 * 24 instead.
I'm sure you can figure out how to print the strings etc. yourself.
(I'd also note - this is a horrible time format, and should be avoided)

Answer 2

You can make a shellscript using awk like this:
str="some string"
startd="12/25/2016"
endd="1/17/2017"
maxloop=10
echo "${maxloop}" |
awk -v string="${str}" -v startdate="${startd}" -v enddate="${endd}" '{
split(startdate,A,"[/]");
T1=mktime(A[3] " " A[1] " " A[2] " 0 0 0");
split(enddate,B,"[/]");
T2=mktime(B[3] " " B[1] " " B[2] " 23 59 59");
linenr=1;
while (T1 < T2) {
printf("%s,%s\n",string,
strftime("%m-%d-%Y",T1));
T1+=3600*24;
if (linenr++ > $1) break;
}
}'
The linenr/maxloop is not adding something to the solution but will help against
mistakes in the input values or maintenance of the script.