stdout is the name of the default output file descriptor of a process. Since there is nothing special about `stdout`, you *should not* use this tag. Use [tag:io-redirection] for questions on how to redirect output, use [tag:file-descriptors] for questions on how to manage file descriptors, use [tag:...
4
votes
2answers
29 views
Redirect a portion of a bash script to a file to capture set -x output
I have a bash script and I want to capture a portion of the script with a set -x and redirect that output to a file.
I can see what the ENVFILE is setting but its going to std out.
Is there a way ...
1
vote
1answer
31 views
Having trouble redirecting application output to log file
I have an embedded ARM device running Linux which launches an application on boot. This application has a bunch of "printf(...)" statements in it that I need to view. The normal way I have been ...
0
votes
1answer
27 views
What should my package-manager-like command line tool print to stdout/stderr?
I'm working on a project that will use whatever package manager is available to provision a freshly installed OS. Some examples of package managers could be apt for Ubuntu, brew and brew cask for OSX, ...
0
votes
1answer
54 views
How do these qemu parameters for stdout redirection work?
I am using the following parameters to launch QEMU so that output from the guest would be redirected to the host console:
-chardev stdio,id=virtiocon0
-device virtio-serial
-device virtconsole,...
1
vote
1answer
50 views
How to get the output of timeout command without using a shell script
I am using a ssh command executor in java which runs the command and gets the output in stderr, stdout and an integer exit value. I am trying run a command with timeout like,
timeout 5s COMMAND
...
-1
votes
2answers
54 views
has a file changed of value [closed]
im trying to use pyinotify to detect if a file has changed.
managed to do it this way
def status(argument):
global email_alarm_status
global new_email_alarm
if not email_alarm_status:
...
0
votes
1answer
132 views
Capture stdout from ssh session to local machine
I am having to put together a script that will ssh into devices to run a command such as "show running-config" and save the output to a file on my local machine. I have done similar tasks like this ...
1
vote
2answers
230 views
where is the location of stdin, stdout, stderr file descriptor in AIX(unix)
In my Linux environment, the file descriptors are located on /dev/fd.
Where is the location of stdin, stdout, stderr file descriptor in AIX(unix).
I couldn't find them.
0
votes
2answers
29 views
Bash scripting: Change standard error message for custom one
I have been trying to work on my own little backup script.
I am running into an issue when I run my script and the rm command has nothing to do. I would still like to process the output (aka display ...
0
votes
1answer
44 views
How to print all MAC addresses of devices interacting with wifis in my area to stdout
How do I configure a tool like wireshark, kismet, tcpdump to passively listen to wifi traffic?
How do I get one of these tools to print these MAC addresses to stdout? I want just one MAC address per ...
2
votes
1answer
36 views
Print stderr only if nothing gets written to stdout, otherwise print just stdout discarding stderr
There's a command that always prints stuff to stderr. Such information is never useful except when it doesn't write anything to stdout.
So, is there a simple shell way, tool or command to help ...
3
votes
4answers
385 views
How to slow down the scrolling of multipage standard output on terminal?
On a cluster where I am part of the management team, I often have to go through the multipage standard output of various commands such as sudo find / to look for any troubles such as broken links or ...
0
votes
1answer
34 views
System messages in vim
O/S: Arch Linux (Kernel 4.3.3-2-ARCH)
While editing files with VIM 7.4 it occassionally happens that system messages appear on the screen, ruining my workflow but obviously not altering the contents ...
0
votes
1answer
30 views
Redircting stdout to file, but duplicating stderr to both file and terminal [duplicate]
Redirecting stderr to file and duplicating stdout to both file and terminal is easy:
$ prog 2>error.log | tee output.log
tee will duplicate stdout, printing it to both terminal and output.log.
...
2
votes
1answer
114 views
How to sort files separately without merging?
File1:
Brazil
New Zealand
Argentina
Uruguay
File2:
Chile
Russia
Latvia
Switzerland
I realize that the command
sort -n File1 File2
will sort all the files merged together and display it in ...
0
votes
0answers
44 views
save outputs and errors to external file from lxterminal
I run compiled python program like this on my linux box (runs automatically after start lxterminal LXDE lxsession autostart):
@lxterminal -e sudo /home/user/app.exe > /home/user/app.out 2>&...
21
votes
4answers
2k views
How to invoke vim editor and pipe output to bash
Sometimes I need to write text and then pipe that text into another command. My usual workflow goes something like this:
vim
# I edit and save my file as file.txt
cat file.txt | pandoc -o file.pdf # ...
1
vote
1answer
73 views
System is no longer outputting UTF-8 characters
I just had an issue with my server where it responded incredibly slowly, so I forced it to reboot over SSH. When I connected back, I found out my system no longer outputs certain characters correctly.
...
8
votes
5answers
549 views
Is there a tool to dynamically redirect output to a new file on request
I'm currently redirecting the output of a monitoring tool to a file, however what I'd like to do, is to redirect this output to a new file on my request (using a keybinding), without stopping the said ...
2
votes
1answer
86 views
non-blocking/multi-threaded cat
cat is blocking from what I see in the code, i.e. it uses blocking read() and then it uses blocking write().
I want to call some tool where I disable all stdout buffering by purpose (e.g. like ...
3
votes
2answers
63 views
stdbuf supposed behavior for subprocesses
I didn't exactly find something about the following in the man-page. How is the supposed behavior in subprocesses spawned by a process which was itself spawned by stdbuf?
E.g.:
stdbuf -oL myprog
...
0
votes
1answer
87 views
How do I output stderr/stdout of my script to both a file and the console?
I'm using Amazon Linux and writing a script in bash. I want to output both stderr / stdout (preferably in the order that they occur) to a file as well as the console. However, this command isn't ...
2
votes
1answer
114 views
Unable to redirect stdout/stderr to log file [duplicate]
I have a script tmp.sh
#!/bin/bash
echo hello
sleep 3
echo 3
I want to log the script running time (as well as script stdout) to a log file.
user$ time ./tmp.sh >& log.tmp
real 0m3....
3
votes
2answers
316 views
What are the default stdin and stdout of a child process?
I would like to know what are the default stdin and stdout of a child process (if there are such defaults). Are stdin and stdout of a child process the same as its parent process? Is this something ...
1
vote
1answer
48 views
Save number of lines output to a variable in a shell script without consuming the output
I have a shell script where I have a if statement based off of the number output lines output from another call. (In my case do something there is more that 1 line of output).
LINES=$(function_call | ...
1
vote
2answers
42 views
redirect the output of {time}
I am trying to benchmark a single request agains a webserver, and am having a problem doing so, specifically, I am having an issue redirecting the output of the time command.
If i simply run
time ...
0
votes
1answer
23 views
Check if stdout is attached to a terminal from an AWK script
Is there any way I can check if an AWK script's stdout is attached to a terminal, just like test -t 1 in a shell?
0
votes
2answers
123 views
Will the stdout output of a background process be taken as the stdin input of the foreground process?
When a background process outputs to stdout to appear on terminal, will the output be taken as stdin input to the foreground process?
Note that the background and foreground process are not related by ...
0
votes
2answers
168 views
Redirect stdout to file with nohup doesn't work
I'm trying to run a C-program in the background. I also want to save the stdout-outputs of the program.
But if I try the following, nohup only redirects stderr-outputs to the logfile.txt:
nohup ./...
1
vote
2answers
46 views
I want to catch the STDERR and STDOUT of Background running script
I have to run a script background and also i have to catch the STDERR and STDOUT . i'm using the below line .
test.sh & >> log_file 2>&1
But un fortunately nothing is getting ...
3
votes
3answers
159 views
Direct output to pipe and stdout
I was wondering if there is a way to pipe the output of a command and direct it to the stdout. So for example, fortune prints a fortune cookie and also copies it to the clipboard:
$ fortune | tee &...
1
vote
1answer
210 views
`docker logs foo | less` isn't searchable or scrollable but `docker logs foo 2>&1 | less` is
Using either one gives readable text. But only with the stderr redirect can one scroll or type /somepattern and get matches.
Without it searching gives "Nothing to search (press RETURN)" and a ...
0
votes
0answers
21 views
Where is the logging of an application launched from the GUI buffered before being sent to a log file?
This is a fairly difficult question for me to word, but I'll try my best.
When I launch an application from the terminal, say, Banshee as an example (so banshee to launch from terminal), I can see ...
1
vote
2answers
441 views
Read from and write to file from stdin and stdout
I need to continually read from and write to a (virtual) file in bash, without closing the file in between. I'm looking for a program which will open the file for read and write, read from stdin and ...
1
vote
1answer
26 views
Prevent script from generating stdout if called from given program
I want my gnome-terminal to show my current user and host in its titlebar, and that of the remote when I am using ssh.
To do that, I created a script ~/bin/ssh, with ~/bin in my PATH before /usr/bin:
...
4
votes
3answers
205 views
Trying to make sense of bash redirection syntaxes and their outputs
I'm new to Linux and trying to understand how redirections work.
I have been testing various syntaxes for redirecting stdout and stderr to the same file, which don't all produce the same results.
...
3
votes
2answers
144 views
vim: Force specific syntax via command-line argument
When I want to easily read my PostgreSQL schema, I dump it to stderr and redirect it to vim:
pg_dump -h localhost -U postgres dog_food --schema-only | vim -
This gives:
vim does not have a syntax ...
1
vote
2answers
130 views
shell stderr to /dev/null
I have PID file and I want to get PID number so this is what I am doing.
[root@linux ~]# PID=`cat /usr/local/foo/var/run/foo.pid`
[root@linux ~]# echo $PID
3414
sometimes this file doesn't existing ...
0
votes
1answer
47 views
Create a two line text file without anything written to stdout
So basically I want to write a two line file containing this:
This is line one
This is line two
I can easily do this by doing this command in bash:
echo "This is line one\nThis is line two" > ...
2
votes
2answers
84 views
How to store the printout of the last command in a shell variable in urxvt/zsh?
I'd like to have the printout (stdout and stderr) of the last command run within zsh available in a variable ready to use grep, etc on it.
1
vote
0answers
35 views
Suppress warning of rbenv versions if no rubies installed
At the moment I'm working on Ansible role that installs ruby with rbenv. In order not to install same ruby version every time I run setup task I have to check that no needed ruby is already installed. ...
2
votes
2answers
149 views
Output is in console but not part of stdout or stderr
I have a command that outputs the following:
READY
Listening....
HELLO
READY
Listening....
TEST
It is speech recognition from pocketsphinx_continuous.
I need that output redirected to a file, and ...
4
votes
5answers
525 views
Concatenate contents from stdout and from file
How can we concatenate results from stdout (or stderr) and a file into a final file.
For example
ls -a | grep text1
concatenate with file2.txt into a final result (not file2.txt), without storing ...
17
votes
5answers
1k views
How to trick a command into thinking its output is going to a terminal
Given a command that changes its behaviour when its output is going to a terminal (e.g. produce coloured output), how can that output be redirected in a pipeline while preserving the changed behaviour?...
2
votes
3answers
40 views
What is regarded as “ideal” in relation to using stdout/stderr for output in different situations?
I have seen stdout and stderr used in a variety of different ways - as far as I understand, it is common to use stdout for general information and stderr for errors and the like. However, I have also ...
3
votes
1answer
434 views
vimdiff to compare output instead of files
I am trying to compare two command output (no files)
vimdiff "$(tail /tmp/cachain.pem)" "$(tail /etc/pki/ca-trust/extracted/pem/tls-ca-bundle.pem)"
I tried playing with redirection, pipe, and vim - -...
0
votes
4answers
200 views
How to display output of command while also parsing it?
I have two commands, build and deploy. Currently I run build manually, parse its output using my own eyes, and use a value I find in the output as an argument to deploy. The process looks something ...
0
votes
0answers
20 views
Piped sequence - printing
I need to write a piped sequence of commands that prints out a list of all sub directories of a current directory.
In order to get all sub directories of a current directory I use: ls -D
Since I am ...
0
votes
2answers
1k views
how to redirect output of ssh to a file
I want to make ssh connection to my server but I don't want to enter password. I want to save output to a file like so:
$ ssh [email protected] -p 22 1>output 2>&1
but when I run it the output ...
0
votes
4answers
162 views
How to log from inside the script along with stdout
I am aware that I can log using tee
But I want to log from inside my script, at the same time display the content on the stdout.
Example, my code looks something like this:
names=$(print("name1 ...
