FWIW: The standards issues with regex are something that that appears to be coming together well. Or better anyway.
Basically when you are using UNIX tools, IMO, regex use has this sort of feel to it:
This is the way UNIX was overall back in the 90's - XOPEN, SUS, SVID, SYSV, BSD, Torvalds etc.
Henry Spencer ( zoologist) wrote the first open source version of UNIX regex, which then allowed the creation of cascade of modern regex "flavors". Larry Wall appears to have used Spencer's regex as a model for perl regex, for example.
So, if you understand the difference between extended regular expressions (ERE) and basic (BRE) you are well on the way.... to Belgium.
I am having trouble parsing rpm filenames in a shell script.. I found a snippet of perl code that will perform the task but I really don't have time to rewrite the entire script in perl. I cannot for the life of me convert this code into something sed-friendly:
if ($rpm =~ /(*)-(*)-(*)\.(.*)/)... (1 Reply)
I have these two files in current dir:
oos.txt
oos_(copy).txt
I execute this find command:find . -regex './oos*.txt'And this outputs only the first file (oos.txt)! :confused:
Only if I add another asterisk to the find find . -regex './oos*.*txt' do I also get the second file... (7 Replies)
Hi,
Please help me to understand the bold segments in the below regex.
Both are of same type whose meaning I am looking for.
find . \( -iregex './\{6,10\}./src' \) -type d -maxdepth 2
Output:
./20111210.0/src
In continuation to above:
sed -e 's|./\(*.\{1,3\}\).*|\1|g'
Output: ... (4 Replies)
I have the following line of code that works wonders. I just don't completely understand it as I am just starting to learn regex. Can you help me understand exactly what is happening here?
find . -type f | grep -v '^\.$' | sed 's!\.\/!!' (4 Replies)
Hi Guys,
Could you please kindly explain what exactly the below SED command will do ?
I am quite confused and i assumed that,
sed 's/*$/ /'
1. It will remove tab and extra spaces .. with single space.
The issue is if it is removing tab then it should be Î right ..
please assist.... (3 Replies)
I am not a big expert in regex and have just little understanding of that language.
Could you help me to understand the regular Perl expression:
^(?!if\b|else\b|while\b|)(?:+?\s+){1,6}(+\s*)\(*\) *?(?:^*;?+){0,10}\{
------
This is regex to select functions from a C/C++ source and defined in... (2 Replies)
Hi everyone,
This regex looks simple and yet it doesn't make sense how it's manipulating the output.
ifconfig -a
eth0 Link encap:Ethernet HWaddr 00:0c:49:c2:35:6v
inet addr:192.16.1.1 Bcast:192.168.226.255 Mask:255.255.255.0
inet6 addr:... (2 Replies)
I'm trying to get some exclusions into our sendmail regular expression for the K command. The following configuration & regex works:
LOCAL_CONFIG
#
Kcheckaddress regex -a@MATCH
+<@+?\.++?\.(us|info|to|br|bid|cn|ru)
LOCAL_RULESETS
SLocal_check_mail
# check address against various regex... (0 Replies)
Hi,
I need some guidance with understanding this Perl script below. I am not the author of the script and the author has not leave any documentation. I supposed it is meant to be 'easy' if you're a Perl or regex guru. I am having problem understanding what regex to use :confused: The script does... (3 Replies)
Hello All,
While googling on regex I came across a site named Regulex Regulex:JavaScript Regular Expression Visualizer
I have written a simple regex ^(a|b|c)(*)@(.*) and could see its visualization; one could export it too, following is the screen shot.
... (3 Replies)
Discussion started by: RavinderSingh13
3 Replies
LEARN ABOUT ULTRIX
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)