How to check if today is a weekend in bash?

Question

How to check if today is a weekend using bash or even perl?

I want to prevent certain programs to run on a weekend.

Answer 1

printf also has date

printf -v day '%(%a)T'
case $day in 
    Sat|Sun) echo "Hooray!";;
esac

https://ideone.com/wU7C0c - demo

Answer 2

You can use something like:

if [[ $(date +%u) -gt 5 ]]; then echo weekend; fi

date +%u gives you the day of the week from Monday (1) through to Sunday (7). If it's greater than 5 (Saturday is 6 and Sunday is 7), then it's the weekend.

So you could put something like this at the top of your script:

if [[ $(date +%u) -gt 5 ]]; then
    echo 'Sorry, you cannot run this program on the weekend.'
    exit
fi

Or the more succinct:

[[ $(date +%u) -gt 5 ]] && { echo "Weekend, not running"; exit; }

To check if it's a weekday, use the opposite sense (< 6 rather than > 5):

$(date +%u) -lt 6

Answer 3

I am not really sure if this is suited to this question but I wanted to share this it to help others out and this is the closest Stack question to what I was looking for.

This is a shell script that I use for starting an application when i boot my computer, the application cannot connect to its server over the weekend (its down for maintenance as the service doesn't run at weekends (forex trading application).

Information about this script, d is 1 to 7 (mon to sun) h is 24 time. You can adjust this to your own settings, maybe you have a midweek maintenance or any other cause. This is my first ever shell script, so I'm sure there is a better way and if anybody wants make edits, feel free I will review for acceptance (or somebody else may do it)

#!/bin/bash
d=$(date +%u)
h=$(date +%H)
case $d in
    '5')
    # Friday after 10pm
    if (($h >= 22)) ; then  
        exit
    fi
    ;;
    '6')
    # all day saturday
        exit
    ;;
    '7')
    #sunday before 10pm
    if (($h < 22)) ; then  
        exit
    fi
    ;;
    *)
    # any other time run the program

    ;;
esac

Answer 4

This is actually a surprisingly difficult problem, because who is to say that "weekend" means Saturday and Sunday... what constitutes "the weekend" can actually vary across cultures (e.g. in Israel, people work on Sunday and have Friday off). While you can get the date with the date command, you will need to store some additional data indicating what constitutes the weekend for each locale if you are to implement this in a way that works for all users. If you target only one country, then the solution posed in the other answers will work... but it is always good to keep in mind the assumptions being made here.

Answer 5

I like this way of running programs on weekdays:

[[ $(date +%u) -lt 6 ]] && weekday-program

It is a bit tricky construction, but compact and easy to add.

Answer 6

case "$(date +%a)" in 
  Sat|Sun) echo "weekend";;
esac