Nohup redirect stdout and stderr to file. For example: echo hello &> all_output.

Nohup redirect stdout and stderr to file So basically, I want . log hello world When I use nohup and redirect the output to nohup. So run it without nohup and shut it down, then check the output. Source via archive. log is that it creates two separate open file descriptions for your target file, one for stdout and one for stderr. You'd be better off to do exec &> some_log. txt redirects both stdout and stderr to the file all_output. If standard output is a terminal, append output to ‘nohup. Hence, it appends nothing to the log file. stdout is changed and becomes incompatible with our mock function. 2. sh file doesn't work properly. log rather than You can redirect standard output and standard error to different files: nohup myprogram > myprogram. bash command line file descriptors linux stderr stdout. If nohup. I want to use nohup and redirect stdout to a file but I do not need a archive I just want to be able to interactively view the current stdout. If you want to redirect the output to a different file, use the > operator after your command: nohup command > output. To redirect stdout you need to specify a file handle for the output in the STARTUPINFO structure. out file remains empty until I Ctrl-C the command. Improve this answer. You can also use 1 instead of 2 so that stdout gets redirected to the 'file' Share. The file I written can be found here I can see output in both Win8. 4. The script gets that output and saves it to a file. Ask Question Asked 12 years, 5 months ago. Tour Start here for a quick overview of the site Help Center Detailed answers to any questions you might have Meta Discuss the workings and policies of this site If you want to redirect stdout to a file, you have many solutions : Just use your command line to do that. This way the data will be appended to the specified file instead of overwriting it. nohup stands for "no hang up. 2>> file. By default, nohup redirects the command‘s output (both stdout and stderr) to a file called nohup. Although the command still runs and completes correctly, I do not understand why there is a difference in the reporting of this message between my two machines. In csh, you can redirect stdout with the usual > operator, you can redirect both stdout and stderr with the >& operator, you can pipe stdout and stderr with the |& operator, but there is no single operator to redirect stderr alone. The _fileno value of the standard streams is also -2, so you need to reopen stdin, redirect stdout/stderr to file under unix c++ - again. They both have their own write position and write mode (regular vs. Append Both Stdout and Stderr to a File in Bash. How to redirect the output of csh script that runs in background. For a more robust solution that can handle session persistence, consider using terminal multiplexers like tmux or GNU Screen. /output. out already exists, the output is appended to the end of the file. out & or even redirect both stdout and stderr to the same file. log This works fine, but what I now want is to be able to also print the PID of the process running script. log 2>&1 & nohup foo 2>&1 The shell redirects stderr to stdout. Man page for nohup. out in the current directory. For example: echo hello &> all_output. txt Combining the above two, you get: zz. Redirecting stdout and stderr to a file in c++. Why I need it. The nohup command will ignore stdin and will redirect stdout and stderr to a file called nohup. I tried it with a division by zero and got the traceback and "ZeroDivisionError: division by zero" in the same log file than stdout was opened at the same time. mkstemp() file in place of 'file'. Viewed 111k times 25 . Hence, if a method has a local copy of one the variable for any reason (e. log to create this log file and redirect there. Hot Network Questions Why deleting corner points doesn't work Using a named pipe can also work to redirect all output from the pipe with colors to another file. txt, so I added 1>&2 to the crontab, which is supposed to make stderr go into the same place as stdout. log So far, I came up with this code, but unfortunately it only fulfils requirements 1, 2 and 4. \out. I tried the following: nohup I am redirecting stdout and stderr to console. The advantage of pty. log nohup: ignoring input and redirecting stderr to stdout $ cat results. Related. It then invokes nohup, which inherits that situation (stderr and stdout using the same file descriptor). out when STDOUT is not redirected. Follow answered Nov 28, 2010 at 18:27. The usual workaround is to execute the command in a sub-shell, In C how do you redirect stdin/stdout/stderr to files when making an execvp() or similar call? Ask Question Asked 11 years, 11 months ago. log Redirect stdout to a file (>out), and then redirect stderr to stdout (2>&1): command >out 2>&1 Redirect both to a file (this isn't supported by all shells, bash and zsh support it, for example, but sh and ksh do not): To run a Python script in the background and ensure that output is saved, you can use nohup along with the -u option to force the stdout and stderr streams to be unbuffered. out? bash; logging; nohup; Share. 7. redirect stdout and stderr to one file, copy of just stderr to another. out 2> my. >> is an appending redirection so 2>> will append stderr to an existing file (or create it) in the same way >> does for stdin. log and it perform in background process. I assume the extra output is ordinarily hidden as it is directed to stderr. And this one doesn't work since grep doesn't read the STDERR What’s the best way of outputting command’s STDOUT/ERR to a file. ps1 2>&1 | tee . g console1. ). (Well somebody has to read the stdin, and it ain't nohup. fifo each command line redirect it to the pipe as follows <command line> > pipe. js >> file. out’ if possible, ‘$HOME/nohup. These tools allow you to detach and reattach terminal sessions without losing output, making them ideal for long If standard input is a terminal, redirect it from /dev/null. out 2>&1 & or to a different one. write but directly write to the fileno file Usually instead you'd do python -u test. I want to run a task (which takes quite a long time) remotely in Ubuntu Linux Bash via nohup and redirect stdout to a file, e. py > my. If you want the logs to go somewhere else, manage that outside That works fine if you want both stdout (channel 1) and stderr (channel 2) logged to the same file (a single file containing the mixture of both stdout and sterr). The simplest approach is sending both stdout and stderr to the same file. Is there a way to have the redirection write Is it possible to temporarily redirect stdout/stderr in Python (i. In the example I give below, what I do is open the file up and then set cmd's stdout and stderr pipes (these are io. see: How do I capture all of my compiler's output to a file? I am a Linux newbie and I'm running the following Linux command: nohup python my_script. Follow 2>&1 redirects stderr to the same output file as stdout which is in this case nohup2. You can do this with subprocess, but it's not trivial. out. The command I am running looks somewhat like this: nohup script. So, you will need to service that pipe, writing to the Redirect stderr to console and file. 15-alpine3. Share. Thus, you're going to have to do this manually. Swapping their order would have made all stderr+stdout go to the file test. fasta Pfam-A. If standard error is a terminal, To use nohup to redirect stdout and stderr to a file, you can use the following syntax: nohup command > output. nohup python3 main. To avoid this, redirect nohup's stdin, stdout and stderr to /dev/null. You can also redirect stdout and stderr to totally separate files like: Insert a sys. Redirect stderr and stdout in Bash [duplicate] (15 answers) Closed 8 years ago . Windows style : Here's a quick example of a logger class that redirects stdout, stderr and exceptions to a file, while still writting everything to the console: class Logger { #log_stream #stdout_write #stderr_write constructor redirect stdout and stderr to one or more files from inside c++. org Share I'm trying to run a few scripts remotely from a Ruby script and am at a loss with redirecting the output of the command to a file. Those messages are not getting printed into the "cout" and "cerr" log files. I tried variations of:. Comparing Job Control Approaches I have a Linux program which can write information to stdout and stderr. I have run: C:\>python c:\python_script. log 2>&1 & Now to redirect stderr and stdout into /var/log directory as following. Redirecting stdout and stderr to a single file in c++. Redirect stderr to both file and stdout in C. It must not contain any spaces. log; 2>&1 redirects stderr to stdout & at the end of the line runs this in the background so you can continue working at the command prompt. However the main issue remains: redirecting stderr of sudo process to file, unattended. Good. This occurs, because stderr is redirected to stdout before stdout is sent to file. Compatibility is not a problem, the code will only run on Unix systems. Redirect stdout and stderr of an external library in Python. others use the shorthand You can 'hijack' stdout and stderr by replacing the pointers; stdout and stderr are nothing more than FILE *. Note: if you log off while the background command is running, it will be killed. sh to the console when I execute the nohup command. out size exceeds 500KB. The following example, for example, redirects solely stdout to a file. A couple of comments: 1) 2>&1 means takes stderr (which is the second stream) and redirect that to stdout (which is the first) 2) You might want to do >> instead of > for redirecting the output (> will overwrite any log file that was there; >> will append; not sure on your use case which is the appropiate one). NAME nohup - run a command immune to hangups, with output to a non-tty It is used to run a command WITHOUT a tty asociated with it, you can end your session and the command will keep running, thus its output is not attached to a tty therefore not being able to show the output there. nohup dotnet application. Here is an example. txt. to keep stderr output and also redirect it to file. Hot Network Questions Movie with invading spheres Solid Mechanics monograph example: deflection results are same for different materials? On continuity and topology in the kernel theorem of Schwartz Meaning of csh is significantly more limited than bash when it comes to file redirection. 9 WORKDIR /usr/src/app COPY . Correct, file handle 1 for the process is STDOUT, redirected by the 1> or by > (1 can be omitted, by convention, the command interpreter [cmd. out should get created if console. I would like to redirect stderrto a file AND to stdout. Is there a way we could bind the "stdout" and "stderr" also to the same file where "cout" and "cerr" are bound. txt & From time to time I would like to check the progress of the task by looking into the output file: cat out. To avoid losing this output, you‘ll want to redirect it from nohup to a file for record keeping and debugging. So tee doesn't get any stdin at all from the pipe. How to How can _user_ redirect PID as well as stdout and stderr of sudo (and not of the sub-shell it spawns) to file ? I. out # change this to Redirect stderr to stdout in C shell. fifo In another terminal redirect all messages from the pipe to your file. (E. cat pipe. g. out' 6. /program > Output. I have a program (server) and I am looking for a way (script) that will redirect (or better duplicate) all its stdout to file and add timestamp for each entry. /foo. A process started by the nohup command will not inherit the shell’s stdout and stderr. out 2> script. sh nohup: ignoring input and appending Just redirect it somewhere else, so it's not the terminal: nohup bash -c 'echo OUT ; echo ERR >& 2' 2> err You can redirect the stderr back to stdout instead of to a file to keep the output in the terminal, but it doesn't make much sense: nohup is for situations where the terminal might get lost, in which case you'll lose the stderr. Viewed 6k times So my script has a few arguments that I need to set, then I try &>myscript. Modified 12 years, 3 months ago. Then it displays all expected output until the termination of the script. The STDOUT from "echo" command goes to the screen. Nohup requires that I redirect all input and output. Thus second, I'm printing the original stderr to both stdout and the out. Redirect stdout, stderr, cout, cerr to file as well as screen. rb > output. If you're OK with having your application's stderr be directed to the same file as its stdout, you don't need Combined stdout and stderr. We need those stdout/stderr messages also go to the corresponding childlog file. You can redirect both stdout and stderr to one file. Commented Aug 29, 2020 at 19:44. So if you want to use stdout and stderr, you need to build your application as I'm trying to redirect the output of a python script to a file. If stdout or stderr is not associated with an output stream (for example, in a Windows application without a console window), the file descriptor returned is -2. It seems like this isn't so much a shell issue as a *nix issue: there's no way to "split" a file-descriptor to point to two separate things, so the only way to reliably preserve the ordering of stdout and stderr is to dupe the "original" file-descriptors so they're pointing to the same place -- after which point you can't re-distinguish them anymore, because they're I have a init. out if possible, $HOME/nohup. hmm query. Could try redirecting stderr in stdout also, just to check if nohup affects it in some way. Running the same command on my laptop, I get: nohup: ignoring input and redirecting stderr to stdout. hmm is a database file (input); query. d script that starts a python socket server. log 2>>out_err. I know how redirect stderr to file using dup2: err := syscall. 21 Redirect nohup's stderr to nohup. I have a shell script which redirects that output to a file in /var/log. The exact outcome in this case depends on the order in which messages are written, just as if two separate commands were writing to I need to redirect stdout to console along with stdout and stderr redirected to a file. > out. The order in which the redirections are made is crucial. Because the output is sometimes large enough to overwhelm subprocess. nohup always writes stdout and stderr to a file. C++ - Duplicating stdout/stderr to file while keeping console outputs. Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Advertising & Talent Reach devs & technologists worldwide about your product, service or employer brand; OverflowAI GenAI features for Teams; OverflowAPI Train & fine-tune LLMs; Labs The future of collective knowledge sharing; About the company Shell : bash OS : Oracle Linux 6. B. If you then redirect STDOUT (1>logfile), STDERR won't be affected, it will still be pointing to the same fd. tcsh$ hmmscan --domtblout FILEOUTPUT Pfam-A. the ssh-session. The data is basically destructed, so no memory Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Advertising & Talent Reach devs & technologists worldwide about your product, service or employer brand; OverflowAI GenAI features for Teams; OverflowAPI Train & fine-tune LLMs; Labs The future of collective knowledge sharing; About the company I am using Popen to call a shell script that is continuously writing its stdout and stderr to a log file. 329. Here's an example of the command: I know the easiest way to redirect the STDOUT/STDERR is to DUP2 their file descriptors BEFORE forking. output 2>&1 & This approach not only redirects stdout but also allows you to log messages persistently. file 2>&1 & For example, to run the `ls` command and redirect the output to If you want to redirect the output of nohup command to file, just add it at the end of command after > redirection operator. Hot Network Questions Are there emergences of scurvy in Canada? Clustering layer with points representing trees Merge two (saved) Apple II BASIC programs in But I would like to redirect stdout and stderr to the same file(and later restore it again) so that the output is sorted in the same order as it is sorted on the console output when not redirecting stderr and stdout. txt 2>&1 Found here but output is only written once the process completes or is killed. Commented Dec 28, Once a job is started or executed using the nohup command, stdin will not be available to the user and nohup. The one peculiar aspect of using 2>&1 with On my server nohup sleep 1 > nohup. " It is a POSIX command used to run another command or script in the background, even after The first part 2>&1 redirects stderr to stdout (0: stdin, 1:stdout, 2:stderr), and the second redirects that to a file called a. The HUP signal is, by convention, the way a terminal warns dependent processes of logout. But it failed. Dup2(int(fatal_logfile. Redirect stdout to a file and add a timestamp. Redirect stderr to stdout to a file in a script. dll > out. What is nohup?. 7) print statements get logged in the file called my. txt this will redirect stdout, 2>&1 redirects stderr to the same place as stdout while allowing you to simultaneously see the output in your terminal. /mylog. It now looks like this: */1 * * * * sudo /home/pi/coup/sensor. log & interactly view the output tail -F . Just do. So, this one won't do. > client. . When you're writing. See my answer to the related question: Redirect stdout to a file in Python? As filmor commented, you could redirect stdout to some file. Here's the concrete task I'm trying to accomplish. How can I redirect FILEOUTPUT to STDOUT ? Additionally, you can direct stdout and stderr to different places: command > stdout. err & To discard an output, redirect it to /dev/null. out, the default appears to be something nohup command should redirect the output to nohup. *. stderr only gets redirected to one of the output files. Go, on the other hand, just sees it as another command line argument, and passes it as an argument to the program. Commented Jun 22, 2017 at 22:37. cmd 2>&1 | tee -a log. out cannot be created or opened for appending, the output shall be appended to the end of the file nohup. How can this redirects stderr to stdout – rindeal. The order of doing the redirections is important. spawn and subprocess. log file (the -a argument means append). 000s 2>&1 redirects stderr to the same file descriptor as stdout, while 2>1 redirects stderr to a file named 1. 1 When redirecting in bash to stdout or stderr, I actually get redirected to a file. cmd 2>&1 | grep pattern because it will mix the original STDOUT and STDERR. I am using an external, precompiled third-party library that produces a ridiculous amount of output, which I would like to redirect to a log file to keep the console clean. With Bash 4 (or others such as Zsh), as easy as: nohup <some-command> &> output. stdout, but its buffered unless you explicitly stated otherwise. out in the directory specified by the HOME environment variable Note that you don't need to redirect both stderr and stdout, It happens that the command you're running under nohup never writes to stdout or stderr, and that you aren't sending any input to it. 3. – Cbhihe. The file size is increasing because a lot of information is being logged. sh script rather than in crontab. log >> file. log &amp; It works and the script writes the log file but the problem is that python error No, it's not just as safe as the standard >>bar 2>&1. out and console. Where entries 0, 1 and 2 are reserved for stdin, stdout and stderr respectively. 6 to write a simple HTTP server to redirect all requests. #!/bin/bash logfile=nohup. Improve this question. Consequently, if stdin, stdout and stderr are all redirected or closed before the terminal disappears, there's absolutely no need for nohup so long as you use disown. This needs to be done inside a shell script. out & gives no help message. out file is not generated. log 2>&1 & is the correct form. Add a comment | Your Answer Try: $ make 2>&1 | tee your_build_log. In a powershell script, I call a program and want to redirect stdout and stderr to different files, while still showing the output of both in the console. How to redirect output from interactive script to file and console? 19. txt 2>&1 Explanation: FIRST, send STDOUT 1 to zfile. out and I want to run another, nohup command, can I redirect the output to nohup2. Popen for example, don't use sys. txt 2>stderr. I am thinking I can redirect the stdout to a file to for it to be flushed after each output ??? nohup ruby myapp. ) Is there a way to make that log file rotate? (max size, then switch to a different file, keep only a limited number of files) (Similarly, each write() syscall writes to only one file descriptor, which is the source of the problem. The tee command prints stdin to both stdout and file (resemblance with the letter T). disown -ah disown -a Share. /script > script. exe] knows to handle that). stdout. However, if I run: func 1>&1 | tee output. log stderr -> stderr stderr -> err. If the output of the nohup command is redirected to some other file, nohup. It is used some stupid tricks : use exec without command to setup redirections, use tee to duplicates outputs, restart the script with the wanted redirections, If you want stderr to occur on console and only stdout going to /dev/null you can use: yourcommand 2>&1 > /dev/null In this case stderr is redirected to stdout (e. About; Products OverflowAI; Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Redirect stdout and stderr to the same file and restore it. out without the '&' the a. (Via >> and 2>&1. redirect stdout/stderr to file under unix c++ - again. If the program should not terminate you can use: nohup yourcommand & $ sudo nohup /home/ubuntu/test. foo >>bar 2>>bar you're opening the bar file twice with O_APPEND, creating two completely independent file objects[1], each with its own state (pointer, open modes, etc). sh 1> zfile. Then, stdout will go into a file test. out This redirect both stderr and stdout outputs to the file called mylogfile and let everything goes to stdout at the same time. log 2>&1" >> results. Redirecting stderr in csh. nohup ffmpeg -i rtsp: First, I'm redirecting stdout to file and stderr to stdout (stdout line gets to the out. out – ismail. Guarantees that ordering between stdout and stderr is precisely in line with the write calls only exist when they're both served by the same file descriptor, and you can't have them served by the same file descriptor while directing their output to different places, even if they're recombined later. log 2>&1 One thing which I did is the output file and the "terminationMessagePath" is the same as i want the pod termination footprint and the stdout/stderr in the same file. – tomi. Also, some functions, like subprocess. Multiple commands' output can be redirected. And as far as I know, this command works in Windows, Linux or MacOS! For other file redirection techniques, just search the os plus "file redirection" This comes in handy when you started a job but forgot to prefix it with nohup. Note that if you're using these to make log files, then unless you're sending the outut to _uniquely_named_ (eg date-and-time-stamped) log files, then if you run Actually it means “first redirect STDERR to STDOUT, so any errors printed out on STDERR should go to STDOUT. /simple. sh > my_logs/my_script. So the echoed output "error" goes to stderr. The second parameter, lpCommandLine must point to writeable memory because CreateProcess overwrites the I'm trying to redirect stderr to stdout and then out to a file in an init script, The ">/tmp/x. out file is used as the default file for stdout and stderr. stdin - 0 stdout - 1 stderr - 2 If you want to redirect stdout and stderr to log. log. 1 – Le Droid. Put that somewhere near the top, then any and all command output, echo, use &> for redirection, this should redirect stdout and stderr to designated file . Stderr. It is not redirecting it to STDOUT. Also, you can use a tempfile. 000s sys 0m0. Currently I am using I am writing a bash script and need to redirect the stdout and stderr output of a command i run to a single file, prefixing each line with stderr or stdout, accordingly. Follow answered Sep 24, 2011 at 5:53. python demo_stdout. My problem is that I am also trying to capture the PID of the process to save to a file, which I can't seem to do. The -s directs the password prompt to the screen. . PIPE, causing the script to hang, I send the stdout directly to the log file. Hereblock cmds stdout/stderr are sent to seperate files and nothing to display. Instead it is getting printed in the prompt. txt |& program_for_stderr So some combination of the above should work for you -- e. 001s user 0m0. The other way around, it moves stdout to 1008, and then moves stderr to the point that stdout is pointing to, 1008 as From the command line you cannot create a case in which, as you say, nohup only redirects stderr-outputs. txt | tail -F Output. Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Advertising & Talent Reach devs & technologists worldwide about your product, service or employer brand; OverflowAI GenAI features for Teams; OverflowAPI Train & fine-tune LLMs; Labs The future of collective knowledge sharing; About the company Visit the blog I use Python3. py > log. : Your redirections are ineffective as 2>&1 will make stderr go where stdout goes (i. stdout with a file-like object is that they can capture the output at a file descriptor level e. I want to create a rolling file, when the file size increases above a particular size, e. out If standard input is a terminal, redirect it from /dev/null. file No output from the child make command is directed to the output file. Because I want this to run as a daemon, I use nohup to start it. My problem: I have a command that produces output to STDOUT. – Alex Robinson @EnzoChi The redirect 2>&1 tells bash to redirect STDERR to the same fd (file descriptor) as where STDOUT currently goes. If you look at the Frequently Used Arguments in the docs, you'll see that you can pass PIPE as the stderr argument, which creates a new pipe, passes one side of the pipe to the child process, and makes the other side available to use as the stderr attribute. From the image, you can see the redirected stdout & stderr of the commands inside the two different files. 29. So the crontab looks clean: Redirect stdout and stderr to file and stderr to stdout. Use the receiving end of the pipe to extract what was written to the 'old' stdout. out in your command line. This allows you to see real-time output in the nohup. How can I do that? c; http-redirect; stdout; output; stderr; Share. /myscript. py >test. You are also making another, more subtle, mistake. 2>&1 redirects stderr to the current location of stdout, and > file redirects stdout to file. err files. log 2>> file. Do nothing, and use docker logs to review the logs. Popen calls. Method 5: Terminal Multiplexers. When stdout and stderr are two different copies of the same file descriptor, there exists an absolute ordering between writes; but as soon as you want them processed separately, they can't be copies of the same kernelspace object anymore, and ordering becomes undefined). I run a python script on a linux server with nohup like that: nohup python3 . log which directly connects stdout to file output (don't try to read from that file, it's off limits when it's process output file). To save the stdout to a file called stdout and the stderr to a file called stderr, you can do With the first part 1>&2, what you are saying is: "Redirect stdout to stderr". In this comprehensive guide, I‘ll explain what nohup is, The 2>&1 syntax merges stderr into the stdout file. close(1) but before the 'file' is opened to use the handle. I suggest you open a pipe pair first, then used fdopen() to create a new FILE * which is assiocated with the sending end of the pipe, then point stdout to your new FILE. err and everything works as expected; all the output from my python (2. At the same time, I can specify via arguments to produce another output that goes straight to a file. out; stderr follows stdout unless you explicitly redirect it to another file. out . redirect stdout and stderr to files with background process. 0 What's wrong about my script with "ssh + nohup" 5 using nohup -> output to file and console. Ask Question Asked 12 years, 3 months ago. nohup is a POSIX command to ignore the HUP (hangup) signal. log") 2>&1 Could you please help me here? I want both stdout and stderr to go into sensorLog. log I can't tell you why there's no separate option for You redirected stdout to a file when you typed > exhibitor. Further, POSIX mandates that the output goes to the nohup. err & or to the same file: nohup myprogram > myprogram. mkfifo pipe. flush() before the close(1) statement to make sure the redirect 'file' file gets the output. txt >& stderr. I can let this script run over the weekend on the server, while my local machine is shut down). append). Previous Article Master the Art of Linux File Ownership – Simplify Your Life Today! If you're using linux, you can also use output redirection. Redirecting stderr into a temp file. Output that would normally go to the terminal goes to a file called nohup. txt file. log` In your case, something like this should work: disown is a shell builtin which tells bash to remove a process from its recordkeeping -- including the recordkeeping that forwards HUP signals. This is very much unlike 2>&1 which is just calling the dup(2) system call, and makes the stderr and stdout How to redirect stdout and stderr to file and console separately in PowerShell? Go through all the sites, I find basically there are two method, but NEITHER can fully satisfy the requirement & . I'm sshing to another server, running a command with nohup, and trying to write the output of the command to a file. Follow edited Nov 20, 2012 at 8:38. py >> /home/pi/sensorLog. Kazekage Gaara. exec > >(tee -i "output. zz. command 2>&1 > file The &> construct can The way open works, it searches for free entry in file descriptor table. out file. sh > /home/ubuntu/data. fifo > 'my_log_file_with_colours' Perl script redirect stderr and stdout to a file. 7. You can append both stdout and stderr instead of just redirecting at the same time to the same file. sh > output. , display and which it anyway goes). out otherwise. txt ; THEN, send STDERR 2 to STDOUT 1 itself (by using &1 pointer). Is there any way to simultaneously output the log file continuously (to the screen), or alternatively, make the shell script write to both the log file and stdout at the same time? To use, replace command with the command you want to run, and replace stderr_command and stdout_command with your desired pipelines. I tried the following: dup2(fileno(pFile), STDERR_FILENO); /* redirect stderr to file */ which . py > a. You can override this behavior by adding nohup to The nohup command purposefully detaches itself from the stdin, so there is nothing it expects to read in itself, and thus I think what you are really after in this question, is redirecting the output of nohup as the stdin for the next command. Commented Apr 26, 2016 at 15:52. The other, more complicated solution allows you to separate stdout and stderr into 2 different files The trouble with using 1>out_err. However, it does not answer the OP's question on how to force STDOUT (which is where echo sends output) to go to STDERR in tcsh. 0. txt nohup: ignoring input and redirecting stderr to stdout In this case, the output of shell script will be sent to /home/ubuntu/data. Then, execute ‘command’ and redirect its STDOUT to ‘file-name'” – keeping in mind that at this point Instead, the nohup command ignores stdin and redirects stdout and stderr to a file called nohup. zsh behaves the way I like I am using nohup to run a script and redirect its output to a file. We can see this when we start our simple. log redirects STDOUT to the file out. py >> /usr/share/1fed8c03-bc30-4889-952e-46f4c19b6ac1. This works for either the command line or most usefully in a bash script. " You can store the output of a command in a variable by using backticks and redirect stderr to a file using 2>: VARIABLE=`command --opt arg 2> stderr. , if the script starts other processes that can also produce output on stdout/stderr. It redirects stdout but the timestamp added is of the time when the script finishes: To redirect (and append) stdout and stderr to a file, while also displaying it on the terminal, I do this: command 2>&1 | tee -a file. How do I ask nohup not to redirect stderr to stdout if it is detached from terminal? Hot Network Questions Is the cogito, in cogito ergo sum, vague? Your program stdout/stderr will still be available through journalctl (sudo journalctl -u <your program identifier>) but they will also be available in your file of choice. print by default sends data to sys. This is a fairly standard practice, and probably the way shells accomplish it right now. because the stream was passed as a @Anders, this is close, but for general compatibility you need to first get the file descriptors and streams in a working state. To save output to FILE, use 'nohup COMMAND > FILE' Simple example: $ nohup bash -c "time echo 'this is stdout' > results. fasta is also an input file. out so the bar and stderr logging stay in your terminal while the file gets stdout. Fd()), int(os. File handle 2 is STDERR, redirected by 2>. sh >> file. Conditions. py &gt; . Popen-based solutions over replacing sys. I want to have my script write something to the beginning and end of the file, and between the two subprocess. Skip to main content. log 2>&1 This sends all output from the command to myoutput. netCore apps and they have their own logs but sometimes I need to capture unhandled exceptions so I'd like to redirect only the errors to a log file when these type of things happen. you could save stdout to a file, and stderr to both a file and piping to another program (with tee). For example- a simple script that, if the scp command fails, instead of printing the failure message to stderr or stdout (I'm not sure to which it outputs when fail), it outputs it to a As a convenience, the redirection &> can be used to direct both stdout and stderr to the same destination. – Randall Right now, I'd like use nohup and put the redirect command to the start. txt 2>&1 Can someone let me know how can I redirect stdout and stderr to a file and also to console? Skip to main content Stack Overflow dup2(fd, STDOUT_FILENO); dup2(STDOUT_FILENO, STDERR_FILENO); close(fd); Your code is equivalent to the POSIX shell syntax (which is available in all shells whose syntax is based on Bourne shell): 2>&1 >filename which makes stderr go to the old stdout while redirecting stdout to the file. Not sure if that gives an answer, but I'm thinking it diminishes the Now you can try the opposite, and redirect "error" STDERR into the file. I found the below code to redirect both to console and log file, now I need to remove stderr to console. Dockerfile is as below: FROM python:2. file This redirects make output to the output file, however it also causes undesired verbose logging to both the file and stdout. For example: nohup my_script. 0 Redirect nohup Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Advertising & Talent Reach devs & technologists worldwide about your product, service or employer brand; OverflowAI GenAI features for Teams; OverflowAPI Train & fine-tune LLMs; Labs The future of collective knowledge sharing; About the company Even worse, if the rest of your script is doing weird things, like spawning children who then exec / nohup detached background processes, piping into tee can cause your script to hang forever. 1. You can redirect stderr to stdout with 2>&1, and then use tee command. txt 2>&1 But also redirect just stderr to a separate file. txt; In this case , stdout and stderr can still be shown on console, but they will be combined in the same file I have a program whose STDERR output I want to inspect and run grep on etc. 15. How to redirect both stdout redirect nohup stdout and flush. I currently use this in my scripts: exec > >(tee -a "${FILE_Log}" ) exec 2> >(tee -a "${FILE_Log}" >&2) Basically you are telling bash to send the output (both stdout and stderr) to tee's stdin, and since tee is running in the subshell (within the parentheses), it will live as long as your script does. txt" part will redirect stdout (file handle #1). It's rather unlikely, but this solution might stop working with future versions of Python in case the original write method of sys. I've done some research and the furthest I could get was thanks to How to add timestamp to STDERR redirection. 9. However, I can keep the stderr output by. for example. python sslocal -c /etc/shadowsocks. This is mainly to make killing the processes easier. log > f is a shortcut for 1>f which redirects output (>) from stdout (1) to the file f, truncating it if it exists. txt However, is there another way to do this such that I get an accurate value for the exit status? That is, if I test $?, I want to see the exit status of command, not the exit status of tee. Modified 7 years, 10 months ago. The file gets written, but no content is in the file. With the below command ,all stderr and stdout redirect into /tmp/ss. Actually, we’ve seen the message in earlier nohup examples: nohup: ignoring input and appending output to 'nohup. a file (cannot be sure for cron), then nohup does not (re-)redirect stdout but just keeps holding where stdout is currently written I'd recommend to use 1> FILE 2>&1 when redirecting stdout and stderr to the same file. So I could redirect it to STDOUT and use grep, but the problem is, I do not want the original STDOUT content. I'm using Python 3. Pipe (|) only reads from stdout, not stderr. as returned by _get_osfhandle(1)), so first _close FDs 0-2 to free them for reuse. : nohup task > out. But nohup has no way to know that, so it tells you that any input would be discarded and any output would be written to nohup. Create a named pipe . txt & If you want to run it in background: nohup . node server. Also if i do . nohup opens To redirect nohup output to a file, use standard redirection syntax like: nohup command > myoutput. But if I already have one command using nohup with output going to /nohup. I also want to redirect stdout and stderr to a log file. $ sudo nohup It does not pull everything pointing at 1001 and move it to 1008, but simply references stdout and moves it to the file. sh >stdout_and_stderr. Not sure about Windows. txt 2>&1 but none of them work quite right in bash, e. Writers that control where stdout and stderr go) to the file handle. For example, the command ls / /foo will produce both stdout output and stderr output, so we can use it as a test case. linux print to STDOUT and redirect to a file using single command. 1k 14 14 How to redirect both stdout and stderr to a file. 1 CMD & (stdout & stderr) And in the other case your server is still running so it might not have been flushed. out if it has not already been To redirect the stdout to stderr, use your command as follows :-$ command-name 1>&2 where command-name is the command you're going to feed, 1 represents stdout and 2 represents stderr. log this is stdout real 0m0. I have the following code: pid_t pid = fork How do I redirect stdout and/or stderr to a path I have specified in a variable? Note: I don't want to overwrite the variable itself, I want to make std[xxx] write to the file specified in the variable. txt command > stdout. – NZD +1, 2>&1 redirects file descriptor 2 (stderr) to file descriptor 1 (stdout) – Sjoerd. redirect stdout and stderr to different processes. the sudo passwd request ([sudo] 's PID, in that it needs not be stored anymore. your console) and afterwards the original stdout is redirected to /dev/null. /print. txt N. The processes that I'm triggering with this file are . log file and stderr to pipe). stdout -> stdout stdout -> out. How to redirect logs from a background process. Add Redirect stdout and stderr to the same file and restore it. txt 2>&1. This is a good way to get STDOUT and STDERR split from a command sending output to both, and send them to files. If standard output is a terminal, append output to nohup. sh script with nohup: $ nohup . Facebook Twitter Pinterest LinkedIn Reddit Email. txt 1>&2 Now, both stdout and stderr both get put into an email, and nothing gets added to the file. (This makes more sense in a cluster context like Kubernetes: in plain Docker it’s already hard to get at a file, in Kubernetes it’s almost impossible, but kubectl logs works great. out 2> myprogram. And be careful you don't have other threads running that can steal the os's first file handle after the os. for the duration of a method)? Edit: The problem with the current solutions (which I at first remembered but then forgot) is that they don't redirect; rather, they just replace the streams in their entirety. starting server with nohup and redirecting input, output. e. 2>&1 redirects fd2 (STDERR) to fd1 (STDOUT), which is already redirected to the file out. Your problem lies in the file permissions (or a read-only filesystem). json > /tmp/ss. out I can redirect stdout and stderr to a file like below some_command. \test. This is equivalent to echo hello > all_output. # Start server echo "Starting server. Like "copying" one stream-source to Redirect output of nohup in a . In a UCRT GUI app the standard FDs are initialized to the File handle -2 (i. Fd())) But then I don't see how can redirect this another time to stdout. To reproduce the This answer sounds plausible; if stdout is not TTY; it is e. 2 is stderr, so you can just 2> to some other file in order to redirect stderr to a different file than stdout. Below are my 3 attempts 6535 $ nohup: ignoring input and redirecting stderr to stdout $ $ cat MyOutput. txt & Share. Modified 7 years, 6 months ago. I thought the ">" redirected continuously the stdout and stderr and not only at command completion. stdout goes either to one you specify via redirection, or to nohup. 4 I want to save the ouput of a nohup command to file other than nohup. log to redirect stderr to the file. Try this to run and log the output in file. log redirects standard output to the file client. out you could simply do the following: I want to redirect the output of stdout and stderr to a common file:. Viewed 6k times 2 . sh 2> zfile. nohup . If you want to send a nohup process to background but also redirect its output to file, you need to add ampersand only after the filename where you are sending As nohup manual states:. I want to run an executable main and redirect all outputs to /dev/null, meanwhile I measure its runtime with time and write the results to runtime. log to redirect stdout to the file. Stack Overflow. Commented Sep 23, 2011 at 9:42. Since the task is long I also have to run the whole thing with nohup. func 2>&1 | tee output. rrlvsg cxt cjesv uqbpbu ijided piaku uay gito dph kvwa