cmd || true will always return 0, since either cmd succeeds or true does. In your snippet #1, cmd is grep && false. That is always false, since either grep fails or false does.
Your snippet #1 therefore reduces to false || true. That will always return 0.
Since your grep command succeeds:
Regards,
Alister
Hi, first post, so hello to all.
I have a Bash scripting problem that is driving me a bit nutty.
It involves a program called 'convert' which is part of the ImageMagick collection.
Normal usage from the commandline is:
$ convert -resize 120x120 inputfile.jpg outputfile.jpg
This is... (7 Replies)
hi,
please point out what's wrong with my script. im feeding it a list containing fqdn, sit should ssh into each and verify that atleast one of its virtual backup ip resolves into one of its virtual hostnames .. anyway the objective shows in the script... however, im having problems in the ... (4 Replies)
Hi, I am a nbee to Unix, I have used following script to check my tomcat is running or not and restart if it down. but actually it restart my tomcat each time running even my tomcat still running fine:
Script that can run a check and perform an action if the check fails
... (1 Reply)
I want to combine 2 conditional statements by using -o in bash, but it won't work.
if ; then
echo "The number needs to be between 0 and $nr"
fi
Each time i execute the file it says:
./selectCitaat: line 10: syntax error near unexpected token `$1' (3 Replies)
Hi,
Does anyone know any way of making bash prompt extended with conditional content?
Example:
export PS1="] && echo '#' || echo '\$'" # This won't work - prompt is not executed
# export PS1="\$" # This is an existing but also working equivalent
I would like to use more complex... (8 Replies)
I want to let sleep 3 in the background and echo $i
pkglists="a b c d e f g"
f()
{
local i
set -- $pkglists
&& ((i +=2)) && sleep 3 &;echo $i
}
f (3 Replies)
I think(hope) I've got a simple one - I just need to send an email if a mysql query returns any results (ideally - it will never match).
Currently I just pipe the mysql query output to the mail program, but of course that emails regardless of the output( and I check this every 10 minutes from... (5 Replies)
Discussion started by: jcass78
5 Replies
LEARN ABOUT OSX
ppmtosixel
ppmtosixel(1) General Commands Manual ppmtosixel(1)NAME
ppmtosixel - convert a portable pixmap into DEC sixel format
SYNOPSIS
ppmtosixel [-raw] [-margin] [ppmfile]
DESCRIPTION
Reads a portable pixmap as input. Produces sixel commands (SIX) as output. The output is formatted for color printing, e.g. for a DEC
LJ250 color inkjet printer.
If RGB values from the PPM file do not have maxval=100, the RGB values are rescaled. A printer control header and a color assignment table
begin the SIX file. Image data is written in a compressed format by default. A printer control footer ends the image file.
OPTIONS -raw If specified, each pixel will be explicitly described in the image file. If -raw is not specified, output will default to com-
pressed format in which identical adjacent pixels are replaced by "repeat pixel" commands. A raw file is often an order of magni-
tude larger than a compressed file and prints much slower.
-margin
If -margin is not specified, the image will be start at the left margin (of the window, paper, or whatever). If -margin is speci-
fied, a 1.5 inch left margin will offset the image.
PRINTING
Generally, sixel files must reach the printer unfiltered. Use the lpr -x option or cat filename > /dev/tty0?.
BUGS
Upon rescaling, truncation of the least significant bits of RGB values may result in poor color conversion. If the original PPM maxval was
greater than 100, rescaling also reduces the image depth. While the actual RGB values from the ppm file are more or less retained, the
color palette of the LJ250 may not match the colors on your screen. This seems to be a printer limitation.
SEE ALSO ppm(5)AUTHOR
Copyright (C) 1991 by Rick Vinci.
26 April 1991 ppmtosixel(1)