LOOP(1)

NAME
loop - generate numerical indices for shell loops, etc

SYNOPSIS
loop start finish [increment]

DESCRIPTION
Loop generates a sequence of numbers between start and finish inclusive, one per line, on stdout. This is mostly useful for driving loops when writing Shell programs sh(1). The default increment is +1 when start<finish, and -1 when start>finish. An optional increment may be specified. If increment is zero, then the start value will be generated continuously.

Both floating point and integer arguments can be used. On integer arguments, if leading zeros are specified, they will be preserver on output. This is useful for generating sequences of file names which are numbered with leading zeros.

EXAMPLE
for i in `loop 10 30 5`
do
  echo $i
done
Will display the values 10, 15, 20, 25, and 30.

for i in `loop 008 005`
do
  echo $i
done
Will display the values 008, 007, 006, 005.

for i in `loop 0.1 2.9 0.5`
do
  echo $i
done
Will display the values 0.1, 0.6, 1.1, 1.6, 2.1, 2.6.

BUGS
This program just scratches the surface. The shells could benefit from a greater ability to perform math. Limitless opportunities for extensions exist, but this simple version is adequate for most shell scripts dealing with sequences of images, etc.

AUTHORS
John Grosh
Phillip Dykstra
Douglas P. Kingston III
Michael John Muuss

SOURCE
SECAD/VLD Computing Consortium, Bldg 394
The U. S. Army Ballistic Research Laboratory
Aberdeen Proving Ground, Maryland 21005

BUG REPORTS
Reports of bugs or problems should be submitted via electronic mail to <devs@brlcad.org>.