Questions tagged [stdout]
61 questions
399
votes
5 answers
What does 2>/dev/null mean?
I would like a brief explanation of the following command line:
grep -i 'abc' content 2>/dev/null
Naive
- 4,745
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22
votes
3 answers
What is the meaning of & at the end of a command?
I have a startup script line:
pyprogramm >> /dev/null 2>&1 &
Meanings:
>> /dev/null - redirect stdout to null device
2>&1 - redirect stderr to stdout (that is redirected to null device)
but what does the very last & mean?
vico
- 4,447
- 20
- 55
- 87
20
votes
2 answers
systemd on 15.04 won't log stdout of unit
I'm currently trying to make a systemd unit as a web server. Currently, my foo.service file looks as follows:
[Unit]
Description=The Foo Web…
Athan Clark
- 607
- 3
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- 9
15
votes
2 answers
How can I view stdout/stderr of a startup application?
Some of the commands that I have in Startup Applications do not start properly when I login. (In particular I am having trouble with gtk-redshift.) In order to debug, I would like to be able to view stdout/stderr. I haven't found a log file for…
Adam Paetznick
- 2,408
- 2
- 15
- 13
11
votes
1 answer
Why should apt-key output not be parsed?
To validate that the docker gpg key is installed, I ran:
sudo apt-key fingerprint 0EBFCD88 | grep "9DC8 5822 9FC7 DD38 854A E2D8 8D81 803C 0EBF CD88"
Which resulted in the following output:
Warning: apt-key output should not be parsed (stdout is…
jfhr
- 213
- 1
- 2
- 6
8
votes
2 answers
How to get git producing output to a file?
I wanted to write the output of git clone to a file using
git clone https://github.com/someRepository > git_clone.file
But instead I get the output displayed/updated in the terminal like
Cloning to 'someRepository' ...
remote: Counting objects:…
derHugo
- 3,306
- 5
- 30
- 49
8
votes
3 answers
systemd service output to terminal/pty
I am not able to figure out what option to pass in StandardOutput= for a
unit file (.service), where I want to show some messages on the connected terminal
from where the service is started! (console/tty doesn't seem to be what I want)
Maybe…
Ani
- 81
- 2
- 18
5
votes
2 answers
Piping the output of comand columns
I am using lolcat to get the output of ls in color. To do this i have copied /usr/bin/ls to /usr/bin/lsslss (to avoid an endless loop since alias cannot acccept $* or $@) and I have added the function:
ls(){ lsslss $* | lolcat; }
to .bashrc
The…
cohill Oniell
- 103
- 1
- 5
4
votes
2 answers
example of console output that is not written to standard output
It seems read does not write to standard output.
$ cat test.sh
#!/bin/bash
read -p "type a key and Enter" key
echo "the key was $key"
$ ./test.sh
type a key and Enterx
the key was x
$ ./test.sh | tee file
type a key and Enterx
the key was x
$ cat…
H2ONaCl
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4
votes
2 answers
How to redirect dd progress in terminal to a log.txt file but still display it on the terminal during the process?
Here is my script :-
sudo mate-terminal --geometry=50x10 -x sh -c "dd if=/dev/sda of=/dev/sdb status=progress 2>&1 | tee log.txt | md5sum > hash.txt | sha1sum > hash1.txt"
I've seen people giving this suggestion all the time; putting 2>&1. But this…
Najmi
- 63
- 1
- 7
4
votes
2 answers
STDOUT and STDERR redirection for nc
I am trying to make a watchdog bash script which has to check if the port is open, based on the exit status, otherwise should start the daemon. Problem is I can't manage to avoid the script outputting any information by redirecting STDOUT and…
Ricardo Beschieru
- 73
- 1
- 1
- 7
3
votes
1 answer
using ffmpeg in bash script prints video data to stdout
I'm writing a bash script to convert some videos
the problem is when I run ffmpeg directly in terminal it is OK and converts video correctly but when I use it in bash script it prints lots of data (like the dump of video file) in stdout…
Ariyan
- 494
- 3
- 9
- 28
3
votes
1 answer
stderr of terminal in red, even with sudo
I am trying to make a working example for logrotate, and to help me through this I figured it was a good idea to turn stderr to red.
Through some reading, I came upon stderred, which I meant to adopt. I downloaded it, make'd it and it works nicely…
Tfb9
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3
votes
1 answer
When piping output to a file, why are stderr and stdout in the wrong order?
I have a perl script:
warn "1\n";
print "2\n";
warn "3\n";
print "4\n";
I pipe the output to a file:
perl script.pl &> foo
cat foo:
1
3
2
4
Why isn't the output in order, and how do I fix it?
Will Sheppard
- 704
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- 12
3
votes
3 answers
How can I view the stdout / stderr from the bash login shell?
I'm trying to debug a strange issue with my ~/.bash_profile, and I'd like to be able to see if there are any errors / etc printed when it's run. Is there some log or such somewhere that contains the stdout and/or stderr of the login shell process?…
Paul Molodowitch
- 131
- 3