pgmramp(1) General Commands Manual pgmramp(1)NAME
pgmramp - generate a grayscale ramp
SYNOPSIS
pgmramp -lr|-tb | -rectangle|-ellipse width height
DESCRIPTION
Generates a graymap of the specified size containing a black-to-white ramp. These ramps are useful for multiplying with other images,
using the pnmarith tool.
OPTIONS -lr A left to right ramp.
-tb A top to bottom ramp.
-rectangle
A rectangular ramp.
-ellipse
An elliptical ramp.
All flags can be abbreviated to their shortest unique prefix.
SEE ALSO pnmarith(1), pgm(5)AUTHOR
Copyright (C) 1989 by Jef Poskanzer.
24 November 1989 pgmramp(1)
Check Out this Related Man Page
pnmarith(1) General Commands Manual pnmarith(1)NAME
pnmarith - perform arithmetic on two portable anymaps
SYNOPSIS
pnmarith -add|-subtract|-multiply|-difference|-minimum|-maximum. pnmfile1 pnmfile2
DESCRIPTION
Reads two portable anymaps as input. Performs the specified arithmetic operation, and produces a portable anymap as output. The two input
anymaps must be the same width and height.
The arithmetic is performed between corresponding pixels in the two anymaps, as if maxval was 1.0, black was 0.0, and a linear scale in
between. Results that fall outside of [0..1) are truncated.
The operator -difference calculates the absolute value of pnmarith -subtract pnmfile1 pnmfile2, i.e. no truncation is done.
All flags can be abbreviated to their shortest unique prefix.
SEE ALSO pbmmask(1), pnmpaste(1), pnminvert(1), pnm(5)AUTHOR
Copyright (C) 1989, 1991 by Jef Poskanzer. Lightly modified by Marcel Wijkstra <wijkstra@fwi.uva.nl>
26 August 1993 pnmarith(1)
What is the point of this? Whenever I close my shell it appends to the history file without adding this. I have never seen it overwrite my history file.
# When the shell exits, append to the history file instead of overwriting it
shopt -s histappend (3 Replies)