I was working on a script that parsed log files. The file names were log.mmddyy (log.080811). This was a little bit of a learning experience for me (new to shell scripting). I was working on a Solaris 10 box, but I thought I’d do all my dev/testing on Ubuntu. Big mistake. Linux was running bash/gnu tools. Solaris was not. After I figured out how to do it on Ubuntu, I had to figure out how to do it on Solaris (thanks Scott!), then I did it in Powershell (had done something similar already for another script) and since I’m teaching myself Python, I wanted to do it in Python.

Are they the “right” way to do them? They work! Probably not a “right” way to do them, as there is always more than one way to do something

Shell

#!/bin/bash
 
os=`uname`
 
if [ $os == 'Linux' ];
    then
    yesterday="$(date -d 'yesterday' +%m%d%y)"
    echo $yesterday
elif [ $os == 'SunOS' ];
    then
    yesterday=`TZ=GMT+24 date +%m%d%y`
    echo $yesterday
fi

Gnu Date

#!/usr/bin/bash
 
## Get Yesterday
yesterday="$(date -d 'yesterday' +%m%d%y)"

Powershell

$yesterday = (get-date -format mmddyy).adddays(-1)
$yesterday.tostring('MMddyy')

Python

 
import datetime
today = datetime.datetime.today()
one_day = datetime.timedelta(days=1)
yesterday = today - one_day
yesterday.strftime('%m%d%y')

Tags: bash, date, linux, powershell, python, shell, unix, yesterday

This entry was posted on Tuesday, August 16th, 2011 at 17:37:53 and is filed under Programming. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.