Skip to main content

Date Validation in a Shell Script

Well I had numerous occasions to verify something at input of a ksh script.  This could be a date or number of particular string etc.
The most useful commands here are  "grep -E -q"  which returns a return code based on the search condition.  Exploiting this logic, please find sample Date Validation check in ksh shell script
# Date should fall in 2010-01-01  to 2019-12-31
# Script expecting a Date parameter in YYYYMMDD format as input
# This is not a 100% check, but will cover 99% of the scenario's

if [ $# -eq 1 ]
then
echo ${DateFormatInput} | grep -E -q '^201[1-9][01][0-9][0-3][0-9]$'
if [[ $? != 0 ]]; then
echo "Please enter Date in YYYYMMDD format. You Entered $@ "
echo "Quitting.. No action done..."
exit 0
fi
else
echo "Please enter Date as parameter in YYYYMMDD format"
echo "Quitting.. No action done..."
exit 0
fi

This script is useful especially when users enter various formats of date. Like UK employees use dd/mm/yyyy and some use mmddyyyy or some use yymmdd. This check will make users consistent in all your scripts.
grep -E -q '^201[1-9][01][0-9][0-3][0-9]$'
^ -> shows it should start with 201
$ -> means it should end with [0-9] character

Popular posts from this blog

Syslog Standards: A simple Comparison between RFC3164 & RFC5424

Syslog Standards: A simple Comparison between RFC3164 (old format) & RFC5424 (new format) Though syslog standards have been for quite long time, lot of people still doesn't understand the formats in detail. The original standard document is quite lengthy to read and purpose of this article is to explain with examples Some of things you might need to understand The RFC standards can be used in any syslog daemon (syslog-ng, rsyslog etc.) Always try to capture the data in these standards. Especially when you have log aggregation like Splunk or Elastic, these templates are built-in which makes your life simple. Syslog can work with both UDP & TCP  Link to the documents the original BSD format ( RFC3164 ) the “new” format ( RFC5424 ) RFC3164 (the old format) RFC3164 originated from combining multiple implementations (Year 2001)

Create your own Passport Photo using GIMP

This tutorial is for semi-techies who knows a bit of GIMP (image editing).   This tutorial is for UK style passport photo ( 45mm x 35 mm ) which is widely used in UK, Australia, New Zealand, India etc.  This is a quick and easy process and one can create Passport photos at home If you are non-technical, use this link   .  If you want to create United States (USA) Passport photo or Overseas Citizen of India (OCI) photo, please follow this link How to Make your own Passport Photo - Prerequisite GIMP - One of the best image editing tools and its completely Free USB stick or any memory device to store and take to nearby shop A quality Digital camera Local Shops where you can print. Normally it costs (£0.15 or 25 US cents) to print 8 photos Steps (Video Tutorial attached blow of this page) Ask one of your colleague to take a photo  of you with a light background. Further details of how to take a photo  yourself       Take multiple pictures so that you can choose from th

Elastic Beats on pfSense : Installation and configuration

Summary Though in many cases syslog is preferred to transport the pfSense logs to external system, Elastic beats provides quite a niche way to send the logs while modelling the data alongside. This makes it ready-made to send to ElasticSearch directly and get ready-made outcomes like SIEM, performance etc. Pre-reqs A build server (preferably Ubuntu or Fedora) with internet connectivity shell access to pfsense server Basic knowledge of Elastic Stack (filebeat.yml configurations etc) Ensure connectivity is allowed from pfsense machine to your Elastic Stack receiver Setup Summary Connectivity tests Install dependencies in build server (vagrant, virtualbox, gmake, go etc) Download Elastic Beats source Make elastic Beats package for FreeBSD Copy binary packages to pfsense server Configure Beats to send to destination Configure ElasticSearch to view the data Installation Steps Connectivity tests Logon to pfsense server via Shel