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Full Discussion: Fork and Execvp Not Executing Bash Commands From C correctly.
Top Forums Programming Fork and Execvp Not Executing Bash Commands From C correctly. Post 302969173 by Don Cragun on Saturday 19th of March 2016 03:57:13 AM
Old 03-19-2016
First, note that you can cut a couple of processes out of your pipe line by using:
Code:
lsof 2>&1 | awk '/log/ && /openbox/ && c++ { print $10 }'

instead of:
Code:
lsof 2>&1 | grep log | awk '/openbox/ { print $10 }' | sed '1d'

Then a few comments about your C code:
  1. The fork() function returns 0 in the child (if a child is created successfully) and returns the PID of the child in the parent (if a child is created successfully), or returns -1 in the parent (if a child could not be created). Your code assumes that fork() never fails! Don't make that assumption.
  2. Operands like 2>&1, |, and grep are shell directives; not operands to be passed to the lsof utility.
  3. Instead of executing lsof, you probably need to execute sh with arguments -c and lsof 2>&1 | awk '/log/ && /openbox/ && c++ { print $10 }'.
This User Gave Thanks to Don Cragun For This Post:
Azrael
 

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LEARN ABOUT CENTOS

bashbug

BASHBUG(1)						      General Commands Manual							BASHBUG(1)

NAME

       bashbug - report a bug in bash

SYNOPSIS

       bashbug [--version] [--help] [email-address]

DESCRIPTION

       bashbug	is  a shell script to help the user compose and mail bug reports concerning bash in a standard format.	bashbug invokes the editor
       specified by the environment variable EDITOR on a temporary copy of the bug report format outline. The user must fill  in  the  appropriate
       fields  and  exit  the  editor.	 bashbug  then	mails the completed report to bug-bash@gnu.org, or email-address.  If the report cannot be
       mailed, it is saved in the file dead.bashbug in the invoking user's home directory.

       The bug report format outline consists of several sections.  The first section provides information about the  machine,	operating  system,
       the  bash  version, and the compilation environment.  The second section should be filled in with a description of the bug.  The third sec-
       tion should be a description of how to reproduce the bug.  The optional fourth section is for a proposed fix.  Fixes are encouraged.

ENVIRONMENT

       bashbug will utilize the following environment variables if they exist:

       EDITOR Specifies the preferred editor. If EDITOR is not set, bashbug defaults to emacs.

       HOME   Directory in which the failed bug report is saved if the mail fails.

       TMPDIR Directory in which to create temporary files and directories.

SEE ALSO

       bash(1)

AUTHORS

       Brian Fox, Free Software Foundation
       bfox@gnu.org

       Chet Ramey, Case Western Reserve University
       chet@po.cwru.edu

GNU Bash-4.0							   1998 July 30 							BASHBUG(1)
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