Login or Register to Ask a Question and Join Our Community

Sponsored Content
Full Discussion: what does this command do?
Top Forums Shell Programming and Scripting what does this command do? Post 302190399 by era on Tuesday 29th of April 2008 02:30:06 PM
Old 04-29-2008
exec in this form is for redirecting the file descriptors of the process.

Think of it this way; if you always want to do "myscript 2>/tmp/fnord 1>&2" then you can say this inside myscript, right at the beginning:

Code:
exec 2>/tmp/fnord 1>&2

Then the redirections are no longer needed at the prompt when you run myscript.

So in your example, the script's input file descriptor (what every command will be reading from if not given a file argument -- read, cat, grep, you name it) from that point on is /dev/console, output from all commands will go to /dev/console (unless separately redirected, of course), and errors will go to the same (2>&1 means send standard error where-ever standard output is).
 

10 More Discussions You Might Find Interesting

1. SuSE

inconsistent ls command display at the command prompt & running as a cron job

Sir, I using the following commands in a file (part of a bigger script): #!/bin/bash cd /opt/oracle/bin ls -lt | tail -1 | awk '{print $6}' >> /tmp/ramb.out If I run this from the command prompt the result is: 2007-05-16 if I run it as a cron job then... (5 Replies)
Discussion started by: rajranibl
5 Replies

2. Shell Programming and Scripting

assign a command line argument and a unix command to awk variables

Hi , I have a piece of code ...wherein I need to assign the following ... 1) A command line argument to a variable e.g origCount=ARGV 2) A unix command to a variable e.g result=`wc -l testFile.txt` in my awk shell script When I do this : print "origCount" origCount --> I get the... (0 Replies)
Discussion started by: sweta_doshi
0 Replies

3. AIX

AIX:Command to get netaddress/subnet address command in IPv4/IP6

AIX:Command to get netaddress/subnet address command in IPv4/IP6 Can anybody help us with a command to retrieve netaddress/subnet address command in IPv4/IP6 on aix machine. net/subnet address is in the format 172.16.212.0(signifies all 255 machines in an IPv4 network) (2 Replies)
Discussion started by: rookie8278
2 Replies

4. Shell Programming and Scripting

Need help! command working ok when executed in command line, but fails when run inside a script!

Hi everyone, when executing this command in unix: echo "WM7 Fatal Alerts:", $(cat query1.txt) > a.csvIt works fine, but running this command in a shell script gives an error saying that there's a syntax error. here is content of my script: tdbsrvr$ vi hc.sh "hc.sh" 22 lines, 509... (4 Replies)
Discussion started by: 4dirk1
4 Replies

5. UNIX for Advanced & Expert Users

unix command : how to insert text at the cursor location via command line?

Hi, Well my title isn't very clear I think. So to understand my goal: I have a script "test1" #!/bin/bash xvkbd -text blabla with xbindkeys, I bind F5 key in order it runs my test1 script So when I press F5, test1 runs. I'm under Emacs/Vi and I press F5 in order to have "blabla" be... (0 Replies)
Discussion started by: xib.be
0 Replies

6. UNIX for Dummies Questions & Answers

passing command output from one command to the next command in cshell

HI Guys, I hope you are well. I am trying to write a script that gets executed every time i open a shell (cshell). I have two questions about that 1) I need to enter these commands $ echo $DISPLAY $ setenv $DISPLAY output_of_echo_$display_command How can i write a... (2 Replies)
Discussion started by: kaaliakahn
2 Replies

7. Shell Programming and Scripting

SH script, variable built command fails, but works at command line

I am working with a sh script on a solaris 9 zone (sol 10 host) that grabs information to build the configuration command line. the variables Build64, SSLopt, CONFIGopt, and CC are populated in the script. the script includes CC=`which gcc` CONFIGopt=' --prefix=/ --exec-prefix=/usr... (8 Replies)
Discussion started by: oly_r
8 Replies

8. Shell Programming and Scripting

Multiple command execution inside awk command during xml parsing

below is the output xml string from some other command and i will be parsing it using awk cat /tmp/alerts.xml <Alert id="10102" name="APP-DS-ds_ha-140018-componentFailure-S" alertDefinitionId="13982" resourceId="11427" ctime="1359453507621" fixed="false" reason="If Event/Log Level(ANY) and... (2 Replies)
Discussion started by: vivek d r
2 Replies

9. AIX

I'm facing problem with rpm command, when running the command and appears this error:

exec(): 0509-036 Cannot load program /usr/opt/freeware/bin/rpm because of the following errors: 0509-022 Cannot load module /opt/freeware/lib/libintl.a(libintl.so.1). 0509-150 Dependent module /opt/freeware/lib/libiconv.a(shr4.o) could not be loaded. 0509-152 Member... (4 Replies)
Discussion started by: Ohmkar
4 Replies

10. UNIX for Beginners Questions & Answers

Another one line command where I'd like to determine if Ubuntu or Red Hat when running command

Hello Forum, I'm making very good progress on my report thanks to the very helpful people on this forum. I've been able to successfully create my report for my Red Hat servers. But I do have a few ubuntu servers in the mix and I'd like to capture some data from them when an ssh connection is... (8 Replies)
Discussion started by: greavette
8 Replies

LEARN ABOUT LINUX

shcomp

SHCOMP(1)						    User Environment Utilities							 SHCOMP(1)

NAME

       shcomp - compile a ksh93 shell script

SYNOPSIS

       shcomp [ options ] [infile] [outfile]]

ORIGIN OF THIS MAN PAGE

       This man page was written by Christophe Martin <Schplurtz@free.fr> for the Debian GNU/Linux system. It is based on "shcomp --man" output.

DESCRIPTION

       Unless  -D  is  specified,  shcomp takes a shell script, infile, and creates a binary format file, outfile, that ksh93 can read and execute
       with the same effect as the original script.

       Since aliases are processed as the script is read, alias definitions whose value requires variable expansion will not work correctly.

       If -D is specified, all double quoted strings that are preceded by $ are output. These are the messages	that  need  to	be  translated	to
       locale specific versions for internationalization.

       If  outfile is omitted, then the results will be written to standard output.  If infile is also omitted, the shell script will be read from
       standard input.

OPTIONS

       -D, --dictionary
	      Generate a list of strings that need to be placed in a message catalog for internationalization.

       -n, --noexec
	      Displays warning messages for obsolete or non-conforming constructs.

       -v, --verbose
	      Displays input from infile onto standard error as it reads it.

       --man  Displays this man page on standard error and exits.

       --help Shows a short help message and exits.

EXIT STATUS

       0      Successful completion.

       >0     An error occurred.

DEBIAN WARNING

       On a Debian GNU/Linux system, more than one package may provide ksh. the output of shcomp can only be used by ksh93.  Any other ksh will be
       unable to run the compiled script.

EXAMPLE

       ( echo '#! /bin/ksh93' ; shcomp myscript ) > myscript.bin &&
       chmod 755 myscript.bin
       ./myscript.bin

SEE ALSO

       ksh(1)

IMPLEMENTATION

       version	       shcomp (AT&T Labs Research) 2003-03-02
       author	       David Korn <dgk@research.att.com>
       copyright       Copyright (c) 1982-2005 AT&T Corp.
       license	       http://www.opensource.org/licenses/cpl1.0.txt

KSH93								  Fri Jun 3 2005							 SHCOMP(1)
All times are GMT -4. The time now is 10:59 PM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy