07-18-2008
Quote:
I was referring to the expression itself.
Ahhh..... sorry, I misunderstood you.
10 More Discussions You Might Find Interesting
1. UNIX for Dummies Questions & Answers
hi,
i got a problem with understanding regular expressions. what i wanna do is
scanning the wtmp logfile for ips and if a specific ip is echoed id like to be a part of a text to be assigned to it.
the scanning is done with
#! /bin/bash
cat wtmp | strings | egrep -o "+\.+\.+\." | sort -u... (6 Replies)
Discussion started by: rocketkids
6 Replies
2. Shell Programming and Scripting
Hi
I have a question on regex
There is a line in a script like
my_file="$(echo SunMonTueWed | sed "s//_&g") "
My question what does the expression _&g do.
Obviously in this example the output is
_Sun_Mon_Tue_Wed
Another question can i use some trick to get the result like... (3 Replies)
Discussion started by: xiamin
3 Replies
3. Shell Programming and Scripting
Hi, im sure this is really simple but i cant quite figure it out. how do i test against a word at the beginning of the line but up to the point of a delimiter i.e. ":"
for example if i wanted to test against the user in the /etc/passwd file
peter:x:101:100:peters account:/var/peter:/bin/sh
... (3 Replies)
Discussion started by: hcclnoodles
3 Replies
4. Shell Programming and Scripting
$var=~ s#(\n?<a>.*?</a>\n)##s
$pat=$1
Recently i came across this bit of a code.
Can someone please explain the function of these two line? (5 Replies)
Discussion started by: King Nothing
5 Replies
5. Shell Programming and Scripting
Hello all
Is there a "not" reversal method for the =~ regex thingy in perl ?
for example, in the snippet below, i have placed a ! in front of the =~ to "not it".. although it quite obviously doesn't work and is just me trying to get across the question in a way that somebody may understand :o... (2 Replies)
Discussion started by: rethink
2 Replies
6. Shell Programming and Scripting
I have a basic question regarding * and . while using regex:
# echo 3 | grep ^*$
3
I think I understood why it outputs "3" here (because '*' matches zero or more of the previous character) but I don't understand the output of the following command:
# echo 3 | grep ^.$
#
I thought I... (7 Replies)
Discussion started by: mirage
7 Replies
7. Shell Programming and Scripting
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)
Discussion started by: suntzu
1 Replies
8. Shell Programming and Scripting
Hi I am trying to match lines having following string
BIND dn="uid=
putting something like this is not working :
/\sBIND dn="uid=/
Any suggestion.
Thanks. John (9 Replies)
Discussion started by: john_prince
9 Replies
9. Shell Programming and Scripting
Hi Guys,
I am trying to work out the regular expression that I would need to capture the below information. I need to find the word SAC followed by using the data thats contained on the next line. I have other expressions that i have configured but none are where the output is on two... (2 Replies)
Discussion started by: mutley2202
2 Replies
10. Shell Programming and Scripting
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)
Discussion started by: alex_5161
2 Replies
LEARN ABOUT CENTOS
shell-quote
SHELL-QUOTE(1) User Contributed Perl Documentation SHELL-QUOTE(1)
NAME
shell-quote - quote arguments for safe use, unmodified in a shell command
SYNOPSIS
shell-quote [switch]... arg...
DESCRIPTION
shell-quote lets you pass arbitrary strings through the shell so that they won't be changed by the shell. This lets you process commands
or files with embedded white space or shell globbing characters safely. Here are a few examples.
EXAMPLES
ssh preserving args
When running a remote command with ssh, ssh doesn't preserve the separate arguments it receives. It just joins them with spaces and
passes them to "$SHELL -c". This doesn't work as intended:
ssh host touch 'hi there' # fails
It creates 2 files, hi and there. Instead, do this:
cmd=`shell-quote touch 'hi there'`
ssh host "$cmd"
This gives you just 1 file, hi there.
process find output
It's not ordinarily possible to process an arbitrary list of files output by find with a shell script. Anything you put in $IFS to
split up the output could legitimately be in a file's name. Here's how you can do it using shell-quote:
eval set -- `find -type f -print0 | xargs -0 shell-quote --`
debug shell scripts
shell-quote is better than echo for debugging shell scripts.
debug() {
[ -z "$debug" ] || shell-quote "debug:" "$@"
}
With echo you can't tell the difference between "debug 'foo bar'" and "debug foo bar", but with shell-quote you can.
save a command for later
shell-quote can be used to build up a shell command to run later. Say you want the user to be able to give you switches for a command
you're going to run. If you don't want the switches to be re-evaluated by the shell (which is usually a good idea, else there are
things the user can't pass through), you can do something like this:
user_switches=
while [ $# != 0 ]
do
case x$1 in
x--pass-through)
[ $# -gt 1 ] || die "need an argument for $1"
user_switches="$user_switches "`shell-quote -- "$2"`
shift;;
# process other switches
esac
shift
done
# later
eval "shell-quote some-command $user_switches my args"
OPTIONS
--debug
Turn debugging on.
--help
Show the usage message and die.
--version
Show the version number and exit.
AVAILABILITY
The code is licensed under the GNU GPL. Check http://www.argon.org/~roderick/ or CPAN for updated versions.
AUTHOR
Roderick Schertler <roderick@argon.org>
perl v5.16.3 2010-06-11 SHELL-QUOTE(1)