Hello all,
Can someone explain to me the advantage between using subshell over a function call in scripts? To me these are the same. Am I wrong to think this? (4 Replies)
I am having a problem getting the PID of a process I start in the background is a csh.
In tcsh and sh it's simple
$! give it to you
But in csh this just returns
Variable syntax
From the man page it should work but it doesn't????
Any help. (2 Replies)
consider the given prg.
main() {
.....
function1(); /* to write into a file or log */
printf(" ");
.....
}
when the control reaches function1(), it should get executed in the
background.At the same time main's printf(" ") statement should also get executed.i.e... (5 Replies)
hello All,
I need to invoke by perl script some program/command and monitor it for 5
minutes . In case it still running for more then 5 min I need to send a signal which will stop it.
I implemeted this as shown below by using eval & alarm
and I'd like to know if there is a better way to... (1 Reply)
Guys,
can you help me in killing the process which is running in back ground under for loop
I am not able to find the PID using ps -afx|grep <word in command I entered> (1 Reply)
Hi all,
I'm reading <advanced bash scripting> and there is a example to kill a background process in a limited time,as shown below:
#! /bin/bash
#set -n
TIMEOUT=$1
count=0
hanging_jobs & {
while ((count < TIMEOUT));do
eval ' && ((count = TIMEOUT))'
((count++))
sleep 1... (6 Replies)
Hello. I was wondering if someone can help me out with something. To simplify my life, I have written a tiny script to open an ssh tunnel through another linux host so that I can access the esxi hosts on that network using the client. For this I have to tunnel ports 443, 902, and 903. Here is what... (1 Reply)
Hey all,
Okay, this one is tricky and I'm not sure there is a niec way to do it, or indeed anyway to do it. The main issue revolves around timing out a hung ssh. I am doing this by creating a wrapper script for the ssh with the following requirements.
My requirements are:
Defineable... (5 Replies)
Here is some back ground on the script. The script is to poll an arbitrary number of DB's. To do this I am creating a function that takes the file_path to the DB and the min poll interval as arguments. The function will be called for each DB and then ran in the background. The function I was... (6 Replies)
Hello All,
I was looking into creating a script that would be used only to start a Daemon and create a lock file...
F.Y.I. It's for Nagios' NRPE Daemon Plugin...
Anyway when I run the command to start the Daemon (below):
/usr/local/nagios/bin/nrpe -c /usr/local/nagios/etc/nrpe.cfg -d
And... (14 Replies)
Discussion started by: mrm5102
14 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)