Questions tagged [stderr]

Standard error is another output stream typically used by programs to output error messages or diagnostics.

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votes
1answer
15 views

Separate stdout and stderr for `docker run`?

Can I get separate stdout and stderr pipes for docker run? Example: $ docker run --rm -it alpine sh -c 'echo this is stdout; echo this is stderr >&2' \ 2> stderr.txt this is stdout this is ...
-6
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2answers
138 views

Standard error to standard output - is there other options beside redirection?

I have very limited understanding about standard error and standard output... One of the common methods is to redirect standard error to standard output. Does it mean that error (which usually goes to ...
0
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1answer
68 views

Issue passing newline `\n` character to curl command

My Jenkins multiline parameter is read in a variable SERVER_IP which is passed to Unix curl command as below: The curl command triggers a webpage(Jenkins Build) and passes the parameters to the ...
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0answers
3 views

How can I suppress cupsfilter debug output?

I have a Ruby program that calls out to the cupsfilter executable on both Linux and Mac OS. On both OS's, there is a lot of debug output going to stderr. Here is an excerpt: DEBUG: argv[0]="...
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1answer
50 views

How to stop stderr output from gcloud command in cron script without stopping all error output?

I have a bash script for a cron job that uses Google Cloud SDK's gcloud command after some conditional statements. eg. gcloud compute firewall-rules update allow-ssh --source-ranges=$(echo "${...
1
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1answer
38 views

Redirect standard error during concatenate using cat

Need some help on redirecting error to stdout for the below command find /mypath/env/test/ -name "*.tmp" -exec cat '{}' ';' >> /mypath/env/final/merged.txt 2>&1 This command ...
1
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1answer
42 views

What does “export >/dev/stderr” mean?

I've found in a bash script following line: export >/dev/stderr what does it mean?
1
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2answers
115 views

Can a program output to STDERR and still return a zero exit status? [closed]

I'm working on refactoring some Python scripts intended to be run from the command line. The scripts use logging, which makes some messages being written to STDERR (among other things). I wonder if it'...
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3answers
100 views

How does > /dev/null 2>&1 work? [duplicate]

I understand how redirecting output with > /dev/null causes it not to print to screen. But for some reason this is not always enough, and some things still do get printed. In those cases > /...
10
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1answer
1k views

POSIX compliant way to redirect stdout and stderr to a file [duplicate]

I am trying to write a script which is POSIX compliant, so it can run on any *nix system (Debian, Fedora, CentOS, AIX, Arch... ALL of them). When it comes to redirection, I am rather confused on what ...
2
votes
1answer
62 views

How do I debug why stderr is being suppressed?

Running some shell functions and ctrl-c-ing them leads to my stderr being suppressed, such that echo hi >&2 and echo hi > /dev/stderr print nothing. I want to debug this, but I have no idea ...
3
votes
1answer
111 views

How to redirect this “Floating point exception(core dumped)” error?

I want to redirect the output of a program to a file with variable name and, at the same time, redirect the possible error. This is the script so far: #!/bin/bash echo "Se ejecutará el PET-linux.x ...
1
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3answers
95 views

Which processes have standard file descriptors?

Which is the correct statement? Every Unix process has the standard file descriptors open: standard input, standard output and standard error. or Every Unix process attached to a terminal has ...
-1
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1answer
24 views

bash won't exit on error if a program's output is redirected to log file

#!/bin/bash exec 200>/var/lock/scraper || exit 1 flock -n 200 || exit 1 cd /home/ubuntu/web_scraper /home/ubuntu/.nvm/versions/node/v13.12.0/bin/node mongo/scraper.js > logs/scraper.log ...
0
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1answer
64 views

Terminal and Grepping Stderr: how do I run a verbose code and grep the standard error without changing anything else?

Suppose I have a code, and it is running in a very verbose mode. This maximum verbosity exposes a message that I'd like to read to see how everything is doing. However, the terminal is flooded with ...
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4answers
415 views

Reading from stderr in c

This is my c program read from stderr i write #include <uninstd.h> #include <stdio.h> int main(void) { char buff[3]; read(2, buff, sizeof(buff)); printf("%s", buff"); return 0; } My ...
1
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1answer
73 views

Is it possible to write an alias or function in Bash to filter out the errors (stderr)?

I sometimes would do grep -ri foo . but in some node_modules, it could have some links to places that don't exist. So I can do a grep -ri foo . 2>&- or grep -ri foo . 2> /dev/null but ...
1
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1answer
122 views

A program's output seems to be neither stdout nor stderr?

I got a program vsftpd which output doesn't seem to be either stdout or stderr (if that's even possible?) My terminal output is: ~# vsftpd 500 OOPS: SSL: cannot load RSA private key I tried to ...
2
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1answer
249 views

Stdout / stderr redirection doesn't work at preventing /dev/tcp/host/port redirection errors

This is normal redirection. user@linux:~$ randomcommand randomcommand: command not found user@linux:~$ 2> user@linux:~$ randomcommand 2> /dev/null user@linux:~$ &> user@linux:~$ ...
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0answers
32 views

Print clang include path and store in file

I'm writing a program that needs to pull in the clang include paths. Thanks to Dump include paths from g++ I'm half-way there. The command I'm using is: clang++ -E -x c++ - -v < /dev/null The ...
0
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1answer
96 views

Use 2>&1 to direct stdout/stderr for a single command only among many in a BASH script

My first post, please be kind :) I'm writing my first ever BASH script, and using systemd to invoke it on a timer (my first systemd units too!). The script runs backups daily, and uses notify-send to ...
2
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1answer
190 views

How to redirect stderr in busybox?

I have BusyBox v1.27.1 (2017-08-03 03:14:35 CEST) built-in shell (ash) on router. I found a weird issue: root@DD-WRT:/# echo -n "Hi" 2>/dev/null -sh: 2: Invalid argument Seems I cannot redirect ...
1
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1answer
29 views

mysqldump into file with any error firing off a cURL request with error information

I'm attempting to setup a backup that I want to execute from the command line where, in the case of an error, it curls the error to an API endpoint. Something like: mysqldump -u whatever -pwhatever ...
1
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2answers
92 views

Add own information to error stream

As is known, we can redirect errors to a specific file with: ./some_script 2>error_log I am running multiple scripts, and would like them to put their errors into a single error file. Is there ...
1
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0answers
60 views

How does redirecting stdout to stderr work [duplicate]

Just trying to redirect stout to stderr. But I'm a little confused about these two commands. echo test 2>/dev/null 1>&2 echo test 1>&2 2>/dev/null I don't understand why the ...
1
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1answer
33 views

Supressing specific error throws from a bash script [closed]

I am using a library that throws a reasonable error when called upen and completes the desired action such that my outputs are as expected. However, as other people will use the script, I think the ...
0
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1answer
135 views

curl still emitting progress info even with --silent option

I have this curl command: curl --silent -o- https://raw.githubusercontent.com/oresoftware/run-tsc-if/master/install.sh | bash || { echo "Could not install run-tsc-if on your system."; exit 1; ...
0
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0answers
52 views

Script - Write stdout and stderr to a file AND to the terminal without pipe [duplicate]

I don't know if it's possible, I would like start a bash script without pipe which write everything to a file and at the same time see the output on the terminal. So I know how to do that with this ...
2
votes
3answers
156 views

How to capture stderr of function that modifies current environment?

The module function of the Environment Modules1 package does its work by modifying various environment variables of the current shell process. Unfortunately, this function returns 0 whether it ...
1
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2answers
33 views

Discard “access denied” stderr natively in find

Is there an option in find that allows me to suppress the error messages that I get from it trying to access directories for which I don't have access? I know I can just discard stderr, but it seems ...
0
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4answers
3k views

How to read stderr from the process running in the background?

I wanna send the daemon into the background and only continue my script execution when the daemon outputs the particular line to the stderr, something among the lines: # Fictional daemon { for x ...
2
votes
2answers
200 views

Openssh client is blocking forever if stderr is redirected to stdout

It seems there might be a problem in the openssh. In the bash shell if I redirect stderr to stdout it's blocking forever, so I have to KeyboardInterrupt: $ ssh -fTNF './config' -MS './sockd5/...
27
votes
3answers
2k views

Is it safe to redirect stdout and stderr to the same file without file descriptor copies?

I start off in empty directory. $ touch aFile $ ls aFile Then I ls two arguments, one of which isn't in this directory. I redirect both output streams to a file named output. I use >> in order ...
1
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0answers
147 views

Curl download speed restricted when down/uploading from stdin/stdout

I'm running 2 curl commands where one downloads all the data into stdout/in until the stack is filled and another uploading whatever is in it out but it seems like the speed is restricted. For the ...
33
votes
5answers
6k views

How to redirect stdout to a file, and stdout+stderr to another one?

How can I achieve cmd >> file1 2>&1 1>>file2 That is, the stdout and stderr should redirect to one file (file1) and only stdout (file2) should redirect to another (both in append ...
4
votes
1answer
276 views

stdout and stderr redirection to different files

How can I redirect stdout to 2 different files and stderr to another, different file? I want something like <my_cmd> 1> file1 file2 2>file3 I know: <my_cmd> | tee file1 file2 > /...
2
votes
1answer
118 views

What is the most succinct way of terminating the rest of a pipeline if a command fails?

Consider the following: command1 | command2 | command3 As I understand pipelines every command is run regardless of any errors which may occur. When a command returns stderr, it is not piped to the ...
1
vote
1answer
334 views

Understanding File Streams and File Descriptors

For extra context, I asked this question earlier, and thought I understood things, but not anymore. I know that echo ignores stdin. I know that stdin, stderr and stdout exist and, in this context, I ...
0
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3answers
462 views

Handle specific error in bash

As a part of my script, I want to publish package to nuget feed: dotnet nuget push package.1.2.3.nupkg --source "mysource" --api-key "mykey" The command may print error: 409 already contains version ...
2
votes
1answer
1k views

What controls the buffering of stdout stderr?

What part of the system sets up the buffering of the three standard streams when a program is started? Is this part of linux, or glibc, or maybe bash? Does POSIX define the behaviour, or is it part ...
1
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0answers
92 views

Color rm -i prompt messages

I'm looking for a way to apply custom colors to messages emitted by the rm -i command: ~ $ rm -i file.txt rm: remove regular empty file 'file.txt'? I understand that I need to redirect the stderr as ...
0
votes
1answer
980 views

How can I store output in bash variable and suppress output to stderr and stdout? [duplicate]

If i'm doing oidvalue=$(snmpget -v 2c -c public localhost 1234) This will store the output of that command in oidvalue, however as it is now, it will print some error to the screen. How can I ...
5
votes
2answers
2k views

Why can't I get pgrep output right to variable on bash script?

I'm trying to make a script to either quit compton if it's running or start it if it's not running. I've read from man that it should exit 1 if process is found, so I've tried to make a script that ...
0
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2answers
753 views

Append string on redirect

When redirecting all output to stderr: stat file >&2 ... if the command throws an error (e.g. file does not exist) how can one prepend some arbitrary text, such as: <<MY ARBITRARY TEXT&...
1
vote
2answers
70 views

Redirect specific error in stderr

So I want to use an if statement to run a script to import some functions. $ cat functions.sh #!/bin/bash sampleFunction(){ if [[ ! "${fakeVariable}" == '2' ]] then read -n1 -r -p "...
0
votes
1answer
231 views

Confusion about stdout and stderr on the start-up terminal

I have an embedded Linux system with different programs running from start-up. Some of these programs write to stdout and stderr with printf(). When I first log into the system via SSH, I can see all ...
0
votes
2answers
2k views

Nohup: Redirect stderr to file and dismiss stdout

Per default, nohup writes stdout to nohup.out and dismisses stderr. I would like to have it the other way around: write stderr to a file and dismiss stdout.
-1
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0answers
47 views

How do I know that the output is stderr? [duplicate]

When writing a very simple command in my terminal, like find ./ -name "pattern" I get a lot of 'errors' because I am not searching as sudo, and as consequence I get a lot of 'Permission denied' ...
-1
votes
1answer
215 views

Gzip verbosity goes to standard error

When I want to redirect any verbose output I usually do the following, [arif@arif test]$ rsync -v /home/arif/storage . 1> stdout [arif@arif test]$ cat stdout storage sent 177 bytes received 35 ...
0
votes
2answers
187 views

STDOUT + STDERR output … is there any difference between considering the output to be an empty string vs NULL

I'm writing some application code that is used to execute Linux shell commands, and it then logs the command details into an SQL database. This includes the output of STDOUT + STDERR (separately). ...