How can we manipulate date in AIX machine using bash script?

Question

My script has one command : date -d -30days . The script when run on Linux machine , runs as expected . However, when run on AIX machine , gives error "illegal option -- d". So, what code/command should be written which will be universal , irrespective of underlying operating system on which the script is run. I need to basically subtract 30 days from current date and use the manipulated date.

You can use Perl: http://stackoverflow.com/a/16028365/1983854 — fedorqui, Oct 08 '14 at 11:00
Well , not well-versed with perl ,need to use bash scripting due to environment restrictions :( — Hitesh Jain, Oct 08 '14 at 11:06
possible duplicate of [Date manipulation in AIX shell script](http://stackoverflow.com/questions/9060519/date-manipulation-in-aix-shell-script) — Etan Reisner, Oct 08 '14 at 13:15
In addition to that possible duplicate [this answer](http://stackoverflow.com/a/21283578/258523) looks like it might be useful. — Etan Reisner, Oct 08 '14 at 13:16
I don't think you will find one command that will be "universal, irrespective of underlying operating system". If you can narrow down the field a bit (i.e. only AIX and Solaris and Linux, but not Windows, DOS, Mac, Multics, Plan 9, ....), you might have better luck... — twalberg, Oct 08 '14 at 17:25

score 0 · Answer 1 · answered Oct 08 '14 at 14:42

"bash scripting" means that you call non-builtin utilities, like date and yes perl.

Since the date command on AIX cannot do what you want it to do, you need to be open to alternatives.

past_date=$(
  perl -MTime::Local -MPOSIX=strftime -le '
    $now = timelocal(0,0,12,(localtime)[3,4,5]); 
    $ago = $now - 30 * 86400; 
    print strftime("%Y-%m-%d %T %Z",localtime($ago))
  '
)

Adjust your strftime format to suit your needs.

I'm assuming your perl distribution is not up-to-date. I would do this instead:

perl -MDateTime -E 'say DateTime->now->set_time_zone("local")->add(days=>-30)->strftime("%F %T %Z")'

How can we manipulate date in AIX machine using bash script?

1 Answers1