Sponsored Content
Top Forums Shell Programming and Scripting Bizzare behavior on redirect of stdout Post 302945353 by edstevens on Thursday 28th of May 2015 01:30:25 PM
Old 05-28-2015
Hmm. Another case of getting so close to the code that one doesn't see it any more. In this case, the deleting of the log file within the script was a vestige of the larger script from which this test piece came. And that script was doing its own logging, rather than redirecting the output as a whole, as in my test. One thing I still don't understand though. Given that I was redirecting stdout of the script as a whole (myscript > myscript.log) even with a command inside the script deleting that same file, would not the next command that generates stdout in the script re-create the specified file?
 

10 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

Redirect stdout and stderr

How can I redirect and append stdout and stderr to a file when using cron? Here is my crontab file: */5 * * * * /dir/php /dir/process_fns.php >>& /dir/dump.txt Cron gives me an 'unexpected character found in line' when trying to add my crontab file. Regards, Zach Curtis POPULUS (8 Replies)
Discussion started by: zcurtis
8 Replies

2. UNIX for Advanced & Expert Users

problem with redirect stdout to file

Hi all hope you can help as I am going MAD!!! :eek: The below is in a shell script but the redirection in the sed line does not work and outputs to the screen and the $fname_2 does note get created ????? Can any one help ?? #!/bin/ksh cd /app/ for fname in `ls -1 X*` do sed 1d $fname... (3 Replies)
Discussion started by: mlucas
3 Replies

3. Shell Programming and Scripting

How to redirect stderr and stdout to a file

Hi friends I am facing one problem while redirecting the out of the stderr and stdout to a file let example my problem with a simple example I have a file (say test.sh)in which i run 2 command in the background ps -ef & ls & and now i am run this file and redirect the output to a file... (8 Replies)
Discussion started by: sushantnirwan
8 Replies

4. Programming

redirect stdout

hello again! i use dup2 to redirect stdout. I run what i want, now i want undo this redirection. how can i do that? thanx in advance (7 Replies)
Discussion started by: nicos
7 Replies

5. Programming

how to redirect back to stdout

In my program, I am using library provided by other. In the library, the cout/cerr is redirected to a file (the file path is known). After I call some methods in the library, I get one side-effect --> The cout/cerr in my own program is also directed to the file. So how can I to redirect... (5 Replies)
Discussion started by: princelinux
5 Replies

6. UNIX for Dummies Questions & Answers

Redirect stdin stdout to multiple files

Hi, i know how to a) redirect stdout and stderr to one file, b) and write to two files concurrently with same output using tee command Now, i want to do both the above together. I have a script and it should write both stdout and stderr in one file and also write the same content to... (8 Replies)
Discussion started by: ysrini
8 Replies

7. Shell Programming and Scripting

redirect STDOUT to a file in a subshell

Hi, I would like to avoid re-directing line by line to a file. What is the best way to re-direct STDOUT to a file in a subshell? Thanks in advance. Cheers Vj (1 Reply)
Discussion started by: tnvee
1 Replies

8. Shell Programming and Scripting

help with counting processes, bizzare behavior

I have a ksh script (dtksh Version M-12/28/93d on Solaris 10) that is run daily by cron and sometime hangs forever. I need to detect if there is an old copy hung before I start the new run, and if so send an email and exit the script. Here is part of the code: #!/usr/dt/bin/dtksh... (4 Replies)
Discussion started by: 73rdUserID
4 Replies

9. Red Hat

Redirect STDOUT and STDERR of chsh

EDIT: Nevermind, figured it out! Forgot to put backslashes in my perl script to not process literals! Hi everyone. I am trying to have this command pass silently. (no output) chsh -s /bin/sh news Currently it outputs. I've tried.... &> /dev/null 1> /dev/null 2>&1 /dev/null 1>&2... (1 Reply)
Discussion started by: austinharris43
1 Replies

10. Shell Programming and Scripting

Redirect stdout and stderror in child process

I have a problem when i try to create a log file from a daemon process using shell scripting in ubuntu 12. Ultimatly what i want to achieve is run a java/jar file from a script. After scourging the internet i found several solutions to do this, the one i choose is to create a startup script that... (4 Replies)
Discussion started by: Narev
4 Replies
Mirror/redirect action in tc(8) 				       Linux					   Mirror/redirect action in tc(8)

NAME
mirred - mirror/redirect action SYNOPSIS
tc ... action mirred DIRECTION ACTION [ index INDEX ] dev DEVICENAME DIRECTION := { ingress | egress } ACTION := { mirror | redirect } DESCRIPTION
The mirred action allows packet mirroring (copying) or redirecting (stealing) the packet it receives. Mirroring is what is sometimes referred to as Switch Port Analyzer (SPAN) and is commonly used to analyze and/or debug flows. OPTIONS
ingress egress Specify the direction in which the packet shall appear on the destination interface. mirror redirect Define whether the packet should be copied (mirror) or moved (redirect) to the destination interface. index INDEX Assign a unique ID to this action instead of letting the kernel choose one automatically. INDEX is a 32bit unsigned integer greater than zero. dev DEVICENAME Specify the network interface to redirect or mirror to. EXAMPLES
Limit ingress bandwidth on eth0 to 1mbit/s, redirect exceeding traffic to lo for debugging purposes: # tc qdisc add dev eth0 handle ffff: ingress # tc filter add dev eth0 parent ffff: u32 match u32 0 0 action police rate 1mbit burst 100k conform-exceed pipe action mirred egress redirect dev lo Mirror all incoming ICMP packets on eth0 to a dummy interface for examination with e.g. tcpdump: # ip link add dummy0 type dummy # ip link set dummy0 up # tc qdisc add dev eth0 handle ffff: ingress # tc filter add dev eth0 parent ffff: protocol ip u32 match ip protocol 1 0xff action mirred egress mirror dev dummy0 Using an ifb interface, it is possible to send ingress traffic through an instance of sfq: # modprobe ifb # ip link set ifb0 up # tc qdisc add dev ifb0 root sfq # tc qdisc add dev eth0 handle ffff: ingress # tc filter add dev eth0 parent ffff: u32 match u32 0 0 action mirred egress redirect dev ifb0 SEE ALSO
tc(8), tc-u32(8) iproute2 11 Jan 2015 Mirror/redirect action in tc(8)
All times are GMT -4. The time now is 02:24 AM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy