Download of the day: Easy date manipulation with yest utility under Linux/UNIX

by on October 12, 2006 · 7 comments· LAST UPDATED October 12, 2006

in , ,

All these years I was using *all dirty shell script hacks* to create my own date manipulation utilities for backups and other admin task. Thanks to this project no more dirty work.

Recently our site visitor Milton left a comment about this nice utility. This utility is very good if you would like to do lots of date manipulation or to crate report/log file names with date in filename.

From the project home page:
yest is a command line date/time manipulation and formatting program, very useful in scripts. You can easily add or subtract days, hours and/or minutes from a specified date. It supports all date command output formats plus more.

This program is called "yest" because the default is to output yesterday's date. This utility knows about leap year, aylight savings time, and such variations.

Task: Install yest

Download yest from project home page. Or use wget command as follows:
$ cd /tmp
$ wget http://easynews.dl.sourceforge.net/sourceforge/yest/yest-2.7.0.3.tgz

Untar the source code:
$ tar -zxvf yest-2.7.0.3.tgz

Compile and install binary
$ su -
# gcc -o /usr/bin/yest yest-2.7.0.3.c

Install man page:
# cp yest-2.7.0.3.man1 yest.1
# gzip yest.1
# cp yest.1.gz /usr/share/man/man1/

How do I use yest?

Following command will display yesterdays date (default):
$ date
Thu Oct 12 23:45:24 IST 2006
$ yest
10/11/2006

Display the date ten days ago (-10 or +10 next 10 days)
$ date
Thu Oct 12 23:46:23 IST 2006

$ yest -10
10/02/2006

$ yest +10
10/22/2006

Format date in dd-mm-yyyy:
$ yest -10 "%d-%m-%Y"
02-10-2006

Get more help
$ yest --help
$ man yest

yest in action

So to executing a script/command on the last day of a month, I was using following script:
#! /bin/bash
TOM=$(TZ=MST-24 date +%d)
if [ $TOM -eq 1 ]; then
# commands or script on the last day of a month
/path/to/mytask
fi

But with yest it is just one line shell script :D
[ $(yest +0 "%d") -eq $(yest "%L") ] && /path/to/mytask || :

=> yest Download is highly recommended tool for all seasoned UNIX admin.

TwitterFacebookGoogle+PDF versionFound an error/typo on this page? Help us!

{ 7 comments… read them below or add one }

1 tiger October 13, 2006 at 7:41 pm

what about using AT or CRON?

> at 00:00 Aug 31
script goes here
ctrl+D

Reply

2 nixCraft October 14, 2006 at 10:57 am

Tiger

Sometime you have 29, 28 (leap year), 30, 31 as month-end day. Sometime day pattern get repeated as 31, 31 (july, aug).

I don\’t just wanna keep changing at command according to month. I manage 100 of boxes I don\’t have time to keep writing at command for each box. So this tool makes for sense to me.

Reply

3 bleh October 14, 2006 at 12:24 pm

ehm… you have never tried

date -d “yesterday” or date -d “+10 days” have you?

date already does all this…

Reply

4 Don Eytel March 21, 2007 at 8:33 pm

Problem compiling an idea.

gcc -o /home/deytel/bin/yest /home/deytel/yest-2.7.0.4.c
/home/deytel/yest-2.7.0.4.c: In function `main':
/home/deytel/yest-2.7.0.4.c:1470: structure has no member named `tm_zone’

Reply

5 nixCraft March 22, 2007 at 10:00 am

May be you need headers files…

Reply

6 Robert June 13, 2007 at 5:43 pm

What about when timezone identifiers change?
Like MST to MDT?

Reply

7 Yogesh August 13, 2007 at 12:46 pm

gr8 …. its rocks on tru64
i hav used following command to compile

cc -o yest yest-2.7.0.3.c
now i can do all date manuculation as i used to do it with GNU date

Thanks

Reply

Leave a Comment

Previous post:

Next post: