Running something on the last day of the month

These scripts run a program on either the last day or last workday of the month. Dates are computed by abusing the hell out of the TZ environment variable. You can do something similar by using a cron entry like this:

58 23 * * * [ `date -d tomorrow +%d` -eq '01' ] && /myscript

Both scripts can be used with or without arguments. If you want to simply check the date:

if lastdom; then
    do something
    do something else
fi

lastdom /path/to/program arg1 arg2 ...

lastwkdom will run if:

• it's Monday-Thursday and the following day is the first, or
• it's a Friday and the following Sunday is either the first or the second.

I've also found it helpful to put a more descriptive header at the top of crontab files:

#============================================================================
# Environment: set CRON so scripts know when they're being run via cron.
CRON=yes
#============================================================================
# Everything on a line is separated by blanks or tabs.
#
#+--------------------------- Minute (0-59)
#|   +----------------------- Hour   (0-23)
#|   |     +----------------- Day    (1-31)
#|   |     |   +------------- Month  (1-12)
#|   |     |   |   +--------- Day of week (0-6, 0=Sunday)
#|   |     |   |   |    +---- Command to be run
#|   |     |   |   |    |
#v   v     v   v   v    v
#----------------------------------------------------------------------------
# Run something on the last day of the month.
8    6  28-31  *   *    lastdom $HOME/cron/some/script

Name Last modified Size Description Parent Directory 08-Jun-2009 14:17 - lastdom 08-Jun-2009 14:04 1k Run something on the last day of the month lastwkdom 08-Jun-2009 14:04 1k Run something on the last workday of the month