Help with use of `` vs exec


 
Thread Tools Search this Thread
Top Forums Shell Programming and Scripting Help with use of `` vs exec
# 1  
Old 04-03-2009
Help with use of `` vs exec

Hi all,
I had an issue regarding use of `` or exec in perl . `` are considered to be unsafe. Why? In my case an user would be giving some parameters as input and I will form an command of it and execute it using ``. It is important to capture output as i have to parse the output. As well as I need to know success or failure of command. There are many such commands so use of open() to execute the command wont help.
I am clearing the input parameters if they contain following metacharacters:
$cmd =~ s/&|;|\`|\"|\*|\?|~|\(|\)|\[|\]|\n|\r/-/g;
Is this a good solution. I assume this is what taint mode does.
If I have to use exec and pass command as array as well as capture output, how can I do that?

Thanks,
Akshay
Login or Register to Ask a Question

Previous Thread | Next Thread

9 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

Script Variables Inquiry, Values Okay in Standalone Exec, No-Show in Cron Exec

I have the following bash script lines in a file named test.sh. #!/bin/bash # # Write Date to cron.log # echo "Begin SSI Load $(date +%d%b%y_%T)" # # Get the latest rates file for processing. # d=$(ls -tr /rms/data/ssi | grep -v "processed" | tail -n 1) filename=$d export filename... (3 Replies)
Discussion started by: ginowms
3 Replies

2. UNIX for Advanced & Expert Users

Using -exec with and without -name

Hi, I need to delete the last N days file using find. I am trying to use find . -mtime -10 -print which lists down required files. but when i use find . -mtime -10 -exec ls -lrt {} \; it gives me all files in the directory including the required files but the required files... (7 Replies)
Discussion started by: v_m1986
7 Replies

3. UNIX for Dummies Questions & Answers

exec

Hi, i don't understand this part of one script exec >> $Log_File 2>&1 (1 Reply)
Discussion started by: messi777
1 Replies

4. Ubuntu

Find and exec

Hello, I am a linux newbe. I want to install a program. I can download it only with wget command from internet. As far as i know this wget command does not transfer the exacutable flags. Because of that i wanted to find all configure files and change their mod to 744. I found this... (1 Reply)
Discussion started by: disconnectus
1 Replies

5. UNIX for Advanced & Expert Users

-exec cp

Hi, on AIX 6.L I want to copy the result of grep -v to test directory then : `hostname`@oracle$ls -l | grep -v RINT -exec cp {} test grep: can't open -exec grep: can't open cp grep: can't open {} test:°`. Can you help me ? Thank you. (3 Replies)
Discussion started by: big123456
3 Replies

6. Shell Programming and Scripting

exec in tcl

Hello; I have a console application who shown a output in every iteration, now i create a small GUI to call the application with button etc..., but what must i do to follow showing the output in the screen? Advanced thanks, Pablo (0 Replies)
Discussion started by: pablodecastillo
0 Replies

7. Shell Programming and Scripting

exec tclsh

As a part of learning shell scripting I was just going through some already created scripts there I found- exec tclsh "$0" $(1+"$@") Here I was able to find what exec ,tclsh does & o/p of same but I could not find usage & output of $(1+"$@"). Can anybody pls expalain me usage details of it? (5 Replies)
Discussion started by: rediffmail
5 Replies

8. UNIX for Advanced & Expert Users

exec

I have read that exec "replaces the current process with a new one". So I did $ exec ls and after this executed, my shell disappeared. I am assuming that my shell had PID xyz, and when I did exec ls, this ls got pid xyz, and when it terminated, there was no more shell process running, and... (5 Replies)
Discussion started by: JamesByars
5 Replies

9. Shell Programming and Scripting

exec

In exec function say when i would like to remove the files exec rm{}\; Why is this "\" needed immediately after {} and what if i dont give it? TIA, Nisha (1 Reply)
Discussion started by: Nisha
1 Replies
Login or Register to Ask a Question
DH-EXEC-INSTALL(1)						      dh-exec							DH-EXEC-INSTALL(1)

NAME
dh-exec-install - Install (and possibly rename) files. SYNOPSIS
#! /usr/bin/dh-exec debian/default.conf => /etc/my-package/start.conf usr/bin/* DESCRIPTION
Being a sub-command of dh-exec(1), this program must not be ran directly, but through dh-exec, which automatically runs all available sub-commands if run bare; or explicitly with dh-exec --with=install. It is meant to be used for dh_install(1) files, and those alone. If it finds that its input is not such a file, it will do nothing, but echo back the contents. The purpose of the program is to extend dh_install(1)'s functionality, by allowing to specify a destination filename. This can be accomplished by a special syntax: the " => " mark between a source and a destination means that the source file should be installed with the specified destination name. For obvious reasons, the source must not be a wildcard, and the destination in this case must be a file, and not a directory. All other non-comment lines are left alone. RESTRICTIONS
Due to the way executable scripts are called from debhelper(1), there is no way to know what options were used for the original dh_install(1). This means, that the --sourcedir option of dh_install(1) will not work correctly when dh-exec-install is in use. IMPLEMENTATION
Internally, the renaming happens by creating a temporary directory under debian/tmp/, and copying (or moving, if the source was under debian/tmp/ to begin with) the file there, with the new name. This is done this way to allow dh_install(1) to do the real copying, and allow its options to continue working, even when renaming is involved. The temporary directory is put under debian/tmp so that it will be cleaned by dh_prep(1) when the clean target gets to run. Thus, no extra code is needed anywhere to clean up the renamed files. ENVIRONMENT
DH_EXEC_SCRIPTDIR Indicates which directory the command-specific scripts should be sought for. If not specified, scripts will be searched for in /usr/share/dh-exec/. FILES
$DH_EXEC_SCRIPTDIR/dh-exec-install-* The various scripts for the higher-level program. SEE ALSO
debhelper(1), dh-exec(1), dh_install(1) AUTHOR
dh-exec-install is copyright (C) 2011-2012 by Gergely Nagy <algernon@madhouse-project.org>. 2012-05-03 DH-EXEC-INSTALL(1)