DELAY(1)

NAME
delay - counts down a specified number of seconds.

SYNOPSIS

  delay [options] <length> [-- command]
  delay [options] until <timespec> [-- command]

DESCRIPTION
The delay program counts down a length of time specified on the command line. By default, it prints out the time remaining once a second. The rate and style of printing can be controlled using options to the program. This includes the ability to supress the printing entirely. It also somewhat supports delaying for fractional seconds.

Delay attempts to compensate for the time it spends printing the updates. There should be no error that is a multiple of the time spent delaying. (There is a bit of error on the startup and termination of the program, but that's unavoidable.)

There are several ways that the time to delay can be specified. The first is that it can be specified as an absolute length of time to delay. This can be in several formats. All of the following formats are allowable. (And equivalent.)

  delay 1d 2:03:04.5
  delay 1d 2h 3m 4.5s
  delay 93785.5
Please note that the fractional seconds code will only work for actual fractional seconds. So, doing things like '0.5h' will delay for half a second, and not for half an hour as one may expect. (But don't rely on this behavior, as it may change in future versions.)

The second format is for a time to delay until be specified. The time parsing code is derived from that used it at, and as a result the time specifications should be described on the at(1) manpage. For example:

  delay until 4 pm
  delay until noon tomorrow
  delay until midnight 13 september 2000
  delay until now + 5 minutes
Please note that the parsing code has a resolution of a minute. So, the last specification would calculate the 5 minutes from the beginning of the current minute, and delay to that absolute point in time. If you need more precision, you can use the first time format, which allows an the delay length to be specified precisely.

If delay sees "--" while parsing it's command line, it stops argument processing. Instead, the argument after the "--" is interpreted as a command to be run when delay completes, and any further arguments are used as arguments to that command. For example:

  delay until 9:30 -- cdplay

OPTIONS
Delay allows you to use command line options to control aspects of its behavior. Here's a list: This enables quiet mode. This prevents delay from outputting the time remaining as it usually does. (This is the default if delay is called with "sleep" as part of the program name.) This enables a minimalistic count of the time remaining, with only the number of seconds left being displayed. This was the default for delay 1.0. This enables the default display. The day, hour, minute, and second are all broken out into seperate entrys. (This is the default, except for the cases where -q is the default.) This enables a more verbose mode of display. (It adds some explanitory text, as compared to -d.) This allows you to specify a custom time prompt. Printf-style formatting is performed, with the following being allowed as the possible percent substitutions:

  %d     Days remaining
  %h     Hours remaining (modulo 24)
  %m     Minutes remaining (modulo 60)
  %s     Seconds remaining (modulo 60)
  %n     Total seconds remaining.
For best results, you'll want to make sure that your custom format stays the same length throughout the count. Printf-style formatting is done on these codes. Use of percent-codes other than the ones listed above will lead to undefined behavior. (Crashes, usually.)

The standard formats can be expressed as custom codes. Here's a list of translations.

  -m    % 8d
  -d    % 3d %02h:%02m:%02s
  -v    Time Remaining: %d days, %02h:%02m:%02s.
This option takes a single parameter, the time in seconds between updates of the time remaining. It need not be a factor of the delay length. It defaults to 1 second, and must be at least that value. If this option is given, a bell character will be sent when time expires. This may be useful in cases where an xterm is send to de-iconify on a bell. If given, delay will display it's version and a short copyright message, and will then exit.

BUGS
The default format is only good for delays of less than 1000 days.

Improper use of the -c option can lead to various problems, and may even have some security implications.

execvp(2) is used to run the command, and this may run programs in the current directory rather than fully respecting your path. Please see the execvp(2) manpage for more details.

AUTHOR
Tom Rothamel <tom-delay@onegeek.org>

WEB SITE
The delay web site is located at:

        http://onegeek.org/~tom/software/delay/

SEE ALSO
the sleep(1) manpage, the printf(3) manpage, the at(1) manpage