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Full Discussion: [Quick question]Problem with execl and GREP
Top Forums UNIX for Dummies Questions & Answers [Quick question]Problem with execl and GREP Post 302695259 by pfpietro on Sunday 2nd of September 2012 11:12:33 AM
Old 09-02-2012
Quote:
Originally Posted by alister
A few items that stand out:
* execl will not do path lookup for "grep".
* read2 prototype doesn't agree with its definition
* fork returns pid_t which you are assigning to an int.

Either your friend mistook printf output for success or they had grep in the current working directory.

Regards,
Alister
I'm using ubuntu 11.04 and compiling with: "gcc filename.c -o filename" or "gcc -g filename.c -o filename " when I have to debug using GDB.

Alister, can you explain me what you meant by
* execl will not do path lookup for "grep".
* read2 prototype doesn't agree with its definition
?

When I use perror I get an error "No such file or directory".
I don't understand why because when I launch the terminal and use "ls" to list all the files, of course I see the file I'm calling the program with. However even if I change the file name for another one or either the file source I still get the same error.

grep works like that, right ? GREP -C PATTERN FILE

so my command line is execl("usr/bin/grep", "grep", "-c", stringa, file, NULL); its supposed to execute GREP -C STRING FILE
but I still get the error.

does anyone can explain me why I'm so blind that I can't see where the problem is ?
 

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LEARN ABOUT DEBIAN

bzegrep

BZGREP(1)						      General Commands Manual							 BZGREP(1)

NAME

       bzgrep, bzfgrep, bzegrep - search possibly bzip2 compressed files for a regular expression

SYNOPSIS

       bzgrep [ grep_options ] [ -e ] pattern filename...
       bzegrep [ egrep_options ] [ -e ] pattern filename...
       bzfgrep [ fgrep_options ] [ -e ] pattern filename...

DESCRIPTION

       Bzgrep  is  used to invoke the grep on bzip2-compressed files. All options specified are passed directly to grep.  If no file is specified,
       then the standard input is decompressed if necessary and fed to grep.  Otherwise the given files are uncompressed if necessary and  fed	to
       grep.

       If  bzgrep  is  invoked as bzegrep or bzfgrep then egrep or fgrep is used instead of grep.  If the GREP environment variable is set, bzgrep
       uses it as the grep program to be invoked. For example:

	   for sh:  GREP=fgrep	bzgrep string files
	   for csh: (setenv GREP fgrep; bzgrep string files)

AUTHOR

       Charles Levert (charles@comm.polymtl.ca). Adapted to bzip2 by Philippe Troin <phil@fifi.org> for Debian GNU/Linux.

SEE ALSO

       grep(1), egrep(1), fgrep(1), bzdiff(1), bzmore(1), bzless(1), bzip2(1)

																	 BZGREP(1)
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