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Top Forums Shell Programming and Scripting meaning of today=${1:-${today}} Post 302612715 by Vidhyaprakash on Monday 26th of March 2012 09:35:14 AM
Old 03-26-2012
meaning of today=${1:-${today}}

what does today=${1:-${today}} mean???

I saw a script which has these two lines:
today=`date '+%y%m%d'`
today=${1:-${today}}

but both gives the same value for $today

Code:
user:/export/home/user>today=`date '+%y%m%d'`
user:/export/home/user>echo $today
120326
user:/export/home/user>today=${1:-${today}}
user:/export/home/user>echo $today
120326
user:/export/home/user>today=
user:/export/home/user>today=${1:-${today}}
user:/export/home/user>echo $today
 
user:/export/home/user>

Can someone please let me know, what actually today=${1:-${today}}
means???
 

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CALENDAR(1)						      General Commands Manual						       CALENDAR(1)

NAME
calendar - reminder service SYNOPSIS
calendar [ - ] DESCRIPTION
Calendar consults the file `calendar' in the current directory and prints out lines that contain today's or tomorrow's date anywhere in the line. Most reasonable month-day dates such as `Dec. 7,' `december 7,' `12/7,' etc., are recognized, but not `7 December' or `7/12'. If you give the month as ``*'' with a date, i.e. ``* 1'', that day in any month will do. On weekends `tomorrow' extends through Monday. When an argument is present, calendar does its job for every user who has a file `calendar' in his login directory and sends him any posi- tive results by mail(1). Normally this is done daily in the wee hours under control of cron(8). The file `calendar' is first run through the ``C'' preprocessor, /lib/cpp, to include any other calendar files specified with the usual ``#include'' syntax. Included calendars will usually be shared by all users, maintained and documented by the local administration. FILES
calendar /usr/libexec/calendar to figure out today's and tomorrow's dates /etc/passwd /tmp/cal* /lib/cpp, egrep, sed, mail as subprocesses SEE ALSO
at(1), cron(8), mail(1) BUGS
Calendar's extended idea of `tomorrow' doesn't account for holidays. 7th Edition October 21, 1996 CALENDAR(1)
All times are GMT -4. The time now is 01:11 AM.
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