I wrote about quoting shell variables not about embedding.
Maybe you true about awk but the "pretty bad" way is universal
It's a bad idea because it becomes language syntax, not merely a string. This is especially bad for a variable, where you might not have strict control over the exact contents:
Quote:
it's for perl
Quote:
...sed, python or almost anything other, where you want to embed shell variables.
I admit there's no good way to do it in sed, but this is an argument against sed, not an argument for that syntax. It's very difficult to safely put variables in sed because so many things need escaping.
And if the argument is that you don't need to memorize syntax for each language, well, you already had to memorize -e for perl, how much harder is -v, shift, etc?
Last edited by Corona688; 06-29-2011 at 12:42 PM..
Hi,
I need to know how I'll be able to write a script that can goto a different dir where I don't have access to read,write and execute and also to run a commandline prompt in that dir with one file whose path has to be specified in that command.
Will I be able to do this?
Any ideas or... (2 Replies)
Hi there,
I have a wapper script which passes the argument from command prompt to inner script.. It works fine as long as the argument containing single word. But when value contains multiple word with space, not working as expected. I tried my best, couldn't find the reason. Gurus, pls.... (2 Replies)
Hi All,
I am working on nawk script, has the small function which prints the output on the screen.Am trying to print/append the same output in a file.
Basically nawk script should print the output on the console/screen and as well it should write/append the same result to a file.
script :... (3 Replies)
Hi..I have the data in a file like in this format, and I need the output time difference in seconds by using awk command. Start date/time and end date/time given in column 2,3 & 4,5. Please assist how to write shell script.
File1.txt
JOB1 10/09/2013 17:42:16 10/09/2013 17:43:46 SU 6202685/1... (4 Replies)
solaris 5.10 Generic_138888-03 sun4v sparc SUNW,Sun-Fire-T200
I need a sed command that tests true when presented with lines that contain either forward and backslash.
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c:/myFile.txt
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Hello all,
I have a question regarding the difference betwen cron and command line.
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Hi,
I'm trying to write a script to determine the time gap between HTTP PUT and HTTP DELETE requests in the HTTP Servers access log.
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In the awk I am trying to subtract the difference $3-$2 of each matching $4 before the first _ (underscore) and print that value in $13.
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Hello,
For my CGI, I have this script :
#!/bin/bash
echo "Content-type: text/html"
echo ""
echo '
<html>
<head>
<meta http-equiv="Content-Type" content="test/html"; charset=UTF-8">
<title> CLF MONITORING </title>
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Discussion started by: Tim2424
4 Replies
LEARN ABOUT CENTOS
shell-quote
SHELL-QUOTE(1) User Contributed Perl Documentation SHELL-QUOTE(1)NAME
shell-quote - quote arguments for safe use, unmodified in a shell command
SYNOPSIS
shell-quote [switch]... arg...
DESCRIPTION
shell-quote lets you pass arbitrary strings through the shell so that they won't be changed by the shell. This lets you process commands
or files with embedded white space or shell globbing characters safely. Here are a few examples.
EXAMPLES
ssh preserving args
When running a remote command with ssh, ssh doesn't preserve the separate arguments it receives. It just joins them with spaces and
passes them to "$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)