2013-05-07



From time to time, I use at(1) to schedule a reminder mail to my-
self  at  some  time in the future. Doing so was always a bit too
much work in my eyes:

     $ at now + 2 weeks
     warning: commands will be executed using /bin/sh
     at> mail -s "a good subject" meillo
     at> some description text
     at> <EOT>
     job 29 at Wed May  7 22:30:00 2013

Recently, I came across the concept of ``Wiedervorlage'', typical
for  German  bureaucracy  and  lawyers, meaning a ``bring forward
file''.  This is exactly what I wanted. Thus, I  wrote  a  script
wv,  which  wraps  around at(1) and mail(1). With wv(1), the same
reminder message is scheduled with:

     $ wv now + 2 weeks
     Subject: a good subject
     some description text
     warning: commands will be executed using /bin/sh
     job 30 at Wed May 22 22:54:00 2013

The script itself:

     #!/bin/sh
     #
     # wv - Wiedervorlage (bring forward file)
     # schedule a reminder mail to yourself at a given date using at(1)
     #
     # markus schnalke <meillo@marmaro.de>

     queue=w

     listone() {
             atq -q "$queue" | awk "/^$1\t/ {sub(/ $queue .*/,\"\");print}"
             at -c "$1" | sed '
                     1,/^# wv/d;
                     /^mail /{s,[^"]*",,; s,".*,,};
                     s,^,\t,
                     '
     }

     list() {
             if [ $# -eq 0 ] ; then
                     atq -q "$queue" | while read id rest ; do
                             listone "$id"
                     done
             else
                     for i in "$@" ; do
                             listone "$i"
                     done
             fi
     }


     if [ $# -eq 0 ] ; then
             cat >&2 <<!
     Usage: ${0##*/} timespec...
            ${0##*/} -l [jobid...]
     !
             exit 1
     fi

     if [ "$1" = "-l" ] ; then
             shift
             list "$@"
             exit
     fi

     printf "Subject: "
     read sub

     at -q "$queue" "$@" <<!
     # wv
     mail -s "Wv: $sub" `id -un`
     `cat`
     !

It uses the at queue `w' in order to  separate  these  jobs  from
other uses of at(1). The input is as simple as I wanted it to be.
Only, I don't get the target date  printed  before  I  enter  the
text,  like `at -v' does. This would require some hacks that com-
plicate the code. The listing  output  is  rudimentary  but  good
enough for my current needs.


What I really hate in Unix are the date  and  time  formats.  IMO
there's  one  true date format (1TDF): ISO 8601. at(1) is a place
were I suffer a lot. I've already wondered  how  much  effort  it
would take to modify a system to only use 1TDF. How much compati-
blity would it break?

It's always the same questions: Adjust the system to your desires
or adjust yourself to the system? Follow the common practice (PO-
SIX) or help to shape the future? Modify existing tools or  write
your own ones?



http://marmaro.de/lue/        markus schnalke <meillo@marmaro.de>