pgmhist(1) General Commands Manual pgmhist(1)NAME
pgmhist - print a histogram of the values in a portable graymap
SYNOPSIS
pgmhist [pgmfile]
DESCRIPTION
Reads a portable graymap as input. Prints a histogram of the gray values.
SEE ALSO pgmnorm(1), pgm(5), ppmhist(1)AUTHOR
Copyright (C) 1989 by Jef Poskanzer.
28 February 1989 pgmhist(1)
Check Out this Related Man Page
ppmhist(1) General Commands Manual ppmhist(1)NAME
ppmhist - print a histogram of a portable pixmap
SYNOPSIS
ppmhist [-hexcolor] [-noheader] [-map] [-nomap] [-sort={frequency,rgb}] [ppmfile]
DESCRIPTION
Reads a PPM image as input. Generates a histogram of the colors in the image, i.e. a list of all the colors and how many pixels of each
color are in the image.
OPTIONS
-sort={frequency,rgb}
The -sort option determines the order in which the colors are listed in the output. frequency means to list them in order of how
pixels in the input image have the color, with the most represented colors first. rgb means to sort them first by the intensity of
the red component of the color, the of the green, then of the blue, with the least intense first.
The default is frequency.
-hexcolor
Print the color components in hexadecimal. Default is decimal.
-noheader
Do not print the column headings.
-map Generates a PPM file of the colormap for the image, with the color histogram as comments.
-nomap Generates the histogram for human reading. This is the default.
SEE ALSO ppm(5), pgmhist(1), ppmtomap(1), pnmhistmap(1), ppmchange(1)AUTHOR
Copyright (C) 1989 by Jef Poskanzer.
17 September 2000 ppmhist(1)
Introduction
Originally, we only had one shell on unix. When ran a command, the shell would attempt to invoke one of the exec() system calls on it. It the command was an executable, the exec would succeed and the command would run. If the exec() failed, the shell would not give up, instead it... (3 Replies)
FreeBSD Kernel Internals, Dr. Marshall Kirk McKusick
nwbqBdghh6E
The first hour of Marshall Kirk McKusick's course on FreeBSD kernel internals based on his book, The Design and Implementation of the FreeBSD Operating System. (0 Replies)
Introduction
I have seen some misinformation regarding Unix file permissions. I will try to set the record straight. Take a look at this example of some output from ls:
$ ls -ld /usr/bin /usr/bin/cat
drwxrwxr-x 3 root bin 8704 Sep 23 2004 /usr/bin
-r-xr-xr-x 1 bin bin ... (6 Replies)
Suppose I have a main() function with only one malloc statement allocating say some 1 gb memory. Also say my system has 1 gb of ram.
main()
{
malloc(1gb)
return(0)
}
The program above exits without freeing the memory.
In this case will the 1 gb of heap memory be returned... (9 Replies)
I see lot of ad-hoc shell scripts in our servers which don't have a shebang at the beginning .
Does this mean that it will run on any shell ?
Is it a good practice to create scripts (even ad-hoc ones) without shebang ? (16 Replies)
Hi everyone,
I know the following questions are noobish questions but I am asking them because I am confused about the basics of history behind UNIX and LINUX.
Ok onto business, my questions are-:
Was/Is UNIX ever an open source operating system ?
If UNIX was... (21 Replies)
A shout out to Scott who gave me a helping hand to turn a simple sample Vue.js app I wrote yesterday into a Vue.js component:
Vue.component("unix-time", {
template: `<div class="time">{{unixtime}}</div>`,
data() {
return {
unixtime: ""
};
},
methods: {
... (1 Reply)
i read here that linux provides no way to determine when a directory was created.
https://www.unix.com/shell-programming-and-scripting/157874-creation-date-directory.htmlI have a directory /home/andy/scripts that had a README file in it.
That file says
I put the script in that directory and... (3 Replies)
Hello.
I can use any particular (stupid or not) format when using bash date command.
Example :
~> date --date "now" '+%Y-%m-%d %H!%M!%S'
2019-06-03 12!55!33or
~> date --date "now" '+%Y£%m£%d %H¤%M¤%S'
2019£06£03 12¤57¤36
or
~> date --date "now" '+%Y-%m-%d %H-%M-%S'
2019-06-03 12-58-51
... (4 Replies)
Morning All
So, I am starting looking into the world of UNIX for a new job (luckily not my primary function!) and I am looking to get stared. Like anything I seem to learn best by trying things out first in an environment but I have a key question:
Currently I use Oracle VirtualBox, can... (8 Replies)
I've installed Slack 14.2 on /dev/sda1 (/dev/sda2 is swap) and FreeBSD 12 on /dev/sda3 and lilo is the boot manager.
FreeBSD slices are as follows;
/ on /dev/ada0S3a, swap on /dev/ada0s3e, /var on /dev/ada0s3b, /tmp on /dev/ada0s3d and /usr on /dev/ada0s3f.
I hesitate to install Solaris 10... (2 Replies)
I'm trying to use a bash script for a psych experiment that involves listening to sound files and responding. If I have something like the code below, how can I make sure that a key press is assigned to RESPONSE only after the second echo statement?
for i in 1 2 3; do
echo "Ready?"
sleep 2
... (10 Replies)