Linux / Unix Shell Scripting: Create Filename By Day Of The Week

Posted on in Categories last updated February 15, 2012

I need to create a log file using the following format:

myapp_monday.log
myapp_tuesday.log
….

myapp_sunday.log

How do I create log filename with day of the week in it under Linux or Unix operating systems?

You can use the date command to display current date and time. You can format a date provide a string beginning with + to get day of the week as follows:
$ date +"%A"
Where,

  • +”%A” – Get weekday in full format i.e. as Tuesday
  • +”%a” – Get weekday in abbreviated format i.e. as Tue
  • +”%u” – Get day of week starting with Monday (1), i.e. mtwtfss
  • +”%w” – Get day of week starting with Sunday (0), i.e. smtwtfs

Use the following syntax to store weekday into a shell variable:

 
_dow="$(date +'%A')"
echo "$_dow"
 
## Get day of week starting with Monday (1), i.e. mtwtfss  (see above for syntax) ##
_dow="$(date +'%u')"
echo "$_dow"

To create a filename with day of the week in it:

#!/bin/bash
 
_dow="$(date +'%A')"
_log="myapp_${_dow}.log"
echo "My log filename: ${_log}"

Sample outputs:

My log filename: myapp_Wednesday.log

Posted by: Vivek Gite

The author is the creator of nixCraft and a seasoned sysadmin and a trainer for the Linux operating system/Unix shell scripting. He has worked with global clients and in various industries, including IT, education, defense and space research, and the nonprofit sector. Follow him on Twitter, Facebook, Google+.

3 comment

    1. @ Mahesh: _dow & _log are just variable names here that represents the data inside is as dayofweek and logs type :)

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