Sponsored Content
Full Discussion: Eval command help
Top Forums Shell Programming and Scripting Eval command help Post 302472174 by nikhilfake on Tuesday 16th of November 2010 12:46:00 PM
Old 11-16-2010
Quote:
Originally Posted by anurag.singh
If myserver is the only word in myfile
Code:
 
ping $(cat myfile)

Actually, myserver is not the only word. It is in a line called
Quote:
Server-Name=myserver
So I used
Code:
ping $(cat myfile | grep "Server-Name" | cut -d'=' -f2)

thanks guys!!!

Last edited by nikhilfake; 11-16-2010 at 01:53 PM..
 

10 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

Access to database/eval command

Hi i have the following code: if(($line!=1) and (@field!='\$')){ print ( "\nTRY TO CONNECT TO DATABASE................\n"); my $dbh = DBI->connect($dsn, $user, $pass); print ("CONNECTED TO DATABASE\n"); eval ... (1 Reply)
Discussion started by: chriss_58
1 Replies

2. Shell Programming and Scripting

Effect of using eval to execute a command as opposed to writing it on the commandline

cmd='date | wc' or cmd="date | wc" $cmdIf this script is executed, an error is generated. The reason written was that "The execution fails because the pipe is not expanded and is passed to date as an argument". What is meant by expansion of pipe. When we execute date | wc on the command line, it... (2 Replies)
Discussion started by: daudiam
2 Replies

3. Shell Programming and Scripting

assignment to variable from eval command

Hi Gurus, I am having 2 parameters as below parm1=value1 parm2=parm1 I want to evaluate parm1 value using eval echo \$$parm2 and later i want to assign this value to other variable which i will be using in if statement like : if ]; then do this....... fi could you please suggest... (5 Replies)
Discussion started by: k_vikash
5 Replies

4. Shell Programming and Scripting

Strange result of eval, how does eval really work with ssh?

Hi all, some small script with eval turned me to crazy. my OS is linux Linux s10-1310 2.6.16.53-0.8.PTF.434477.3.TDC.0-smp #1 SMP Fri Aug 31 06:07:27 PDT 2007 x86_64 x86_64 x86_64 GNU/Linux below script works well #!/bin/bash eval ssh remotehost date eval ssh remotehost ls below... (1 Reply)
Discussion started by: summer_cherry
1 Replies

5. Shell Programming and Scripting

Help with perl eval command .....

Hi All, I read the above written code (perl code) in another perl script and evaluates this code for each line of text file,but using exit statement in code make this not to work and i could not get the desired results. However if i use return it works fine. I just need to know why it doesn't... (1 Reply)
Discussion started by: sarbjit
1 Replies

6. Shell Programming and Scripting

Error in eval eval command to print html tags

anyone has any info on why this is complaining??? vivek@vivek-c5e55ef2e ~/TAC $ zoneCounter=1 vivek@vivek-c5e55ef2e ~/TAC $ optUsage1=23% vivek@vivek-c5e55ef2e ~/TAC $ eval eval echo "<th>Zone $zoneCounter </th><th align=\"left\"> \$optUsage$zoneCounter </th>" -bash: syntax error... (1 Reply)
Discussion started by: vivek d r
1 Replies

7. Shell Programming and Scripting

Error in eval eval command to print html tags

anyone has any info on why this is complaining??? vivek@vivek-c5e55ef2e ~/TAC $ zoneCounter=1 vivek@vivek-c5e55ef2e ~/TAC $ optUsage1=23% vivek@vivek-c5e55ef2e ~/TAC $ eval eval echo "<th>Zone $zoneCounter </th><th align=\"left\"> \$optUsage$zoneCounter </th>" -bash: syntax error... (13 Replies)
Discussion started by: vivek d r
13 Replies

8. Shell Programming and Scripting

Usage of '-' in eval command.

Hi, I am trying to use eval command to evaluate a variable(HAPROXY_LISTENER_rabbitmq_project-test-BRHM_PORT) which consists of '-' but unfortunately the eval command is unable to interpret the value of variable and trims the variable name after '-' and produces the string output rather than the... (10 Replies)
Discussion started by: Kuldip
10 Replies

9. Shell Programming and Scripting

Eval command with space, quote and bracket characters

Hi, I am Pradnya Gandhe trying to use in shell script. I want to use a bit complicated command using eval command in a shell script. <path to>\wsadmin.sh -lang jython -conntype NONE -c "AdminApp.install('war file path', '] -MapWebModToVH ] -MapRolesToUsers ] ]')" Works correctly as expected... (2 Replies)
Discussion started by: Pradnya Gandhe
2 Replies

10. UNIX for Beginners Questions & Answers

[BASH] eval command not expanding variables as expected.

Hi Guys, I wrote a collection of bash functions years ago and now need to use them again but I'm getting some error messages when eval tries to expand the variables names. I recollect that I used the shopt command to set one of the options but I can't quite remember the command that I... (8 Replies)
Discussion started by: ASGR
8 Replies
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)
All times are GMT -4. The time now is 08:37 AM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy