Questions tagged [stderr]
Standard error is another output stream typically used by programs to output error messages or diagnostics.
195
questions
0
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
votes
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
votes
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 ...
0
votes
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]="...
0
votes
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
vote
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
vote
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
vote
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'...
-1
votes
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
votes
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
vote
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
votes
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
votes
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 ...
1
vote
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
vote
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
vote
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
votes
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:~$ ...
0
votes
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
votes
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
votes
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
vote
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
vote
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
vote
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
vote
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
votes
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
votes
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
vote
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
votes
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
vote
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
votes
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
vote
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
votes
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 [[ ! "${fakeVariable}" == '2' ]]
then
read -n1 -r -p "...
0
votes
1answer
231 views
Confusion about stdout and stderr on the start-up terminal
I have an embedded Linux system with different programs running from start-up. Some of these programs write to stdout and stderr with printf().
When I first log into the system via SSH, I can see all ...
0
votes
2answers
2k views
Nohup: Redirect stderr to file and dismiss stdout
Per default, nohup writes stdout to nohup.out and dismisses stderr. I would like to have it the other way around:
write stderr to a file and dismiss stdout.
-1
votes
0answers
47 views
How do I know that the output is stderr? [duplicate]
When writing a very simple command in my terminal, like
find ./ -name "pattern"
I get a lot of 'errors' because I am not searching as sudo, and as consequence I get a lot of 'Permission denied' ...
-1
votes
1answer
215 views
Gzip verbosity goes to standard error
When I want to redirect any verbose output I usually do the following,
[arif@arif test]$ 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).
...
