How do I save terminal output to a file?
How do I save the output of a command to a file? Is there a way without using any software? I would like to know how.
10 Answers 10
Yes it is possible, just redirect the output (AKA stdout ) to a file:
Or if you want to append data:
If you want stderr as well use this:
if you want to have both stderr and output displayed on the console and in a file use this:
SomeCommand 2>&1 | tee SomeFile.txt (If you want the output only, drop the 2 above)
Note that someCommand 2> someFile.txt and someCommand 2>> someFile.txt also redirects stterr to someFile.txt
I’m trying to do this with gcc command but it doesn’t work. It works with other commands, but not this one. It simply creates the output file with nothing inside it.
@Nik-Lz Often this is because the command is sending all its output on stderr. If gcc is generating error messages, this seems likely. See Slothworks comment for how to capture stderr instead of stdout.
NB: to get the output of the make command into a file it requires this syntax instead: make > someFile.txt 2>&1 (source: linuxquestions.org/questions/linux-newbie-8/…)
To write the output of a command to a file, there are basically 10 commonly used ways.
Overview:
Please note that the n.e. in the syntax column means «not existing».
There is a way, but it’s too complicated to fit into the column. You can find a helpful link in the List section about it.
|| visible in terminal || visible in file || existing Syntax || StdOut | StdErr || StdOut | StdErr || file ==========++==========+==========++==========+==========++=========== > || no | yes || yes | no || overwrite >> || no | yes || yes | no || append || | || | || 2> || yes | no || no | yes || overwrite 2>> || yes | no || no | yes || append || | || | || &> || no | no || yes | yes || overwrite &>> || no | no || yes | yes || append || | || | || | tee || yes | yes || yes | no || overwrite | tee -a || yes | yes || yes | no || append || | || | || n.e. (*) || yes | yes || no | yes || overwrite n.e. (*) || yes | yes || no | yes || append || | || | || |& tee || yes | yes || yes | yes || overwrite |& tee -a || yes | yes || yes | yes || append List:
- command > output.txt The standard output stream will be redirected to the file only, it will not be visible in the terminal. If the file already exists, it gets overwritten.
- command >> output.txt The standard output stream will be redirected to the file only, it will not be visible in the terminal. If the file already exists, the new data will get appended to the end of the file.
- command 2> output.txt The standard error stream will be redirected to the file only, it will not be visible in the terminal. If the file already exists, it gets overwritten.
- command 2>> output.txt The standard error stream will be redirected to the file only, it will not be visible in the terminal. If the file already exists, the new data will get appended to the end of the file.
- command &> output.txt Both the standard output and standard error stream will be redirected to the file only, nothing will be visible in the terminal. If the file already exists, it gets overwritten.
- command &>> output.txt Both the standard output and standard error stream will be redirected to the file only, nothing will be visible in the terminal. If the file already exists, the new data will get appended to the end of the file..
- command | tee output.txt The standard output stream will be copied to the file, it will still be visible in the terminal. If the file already exists, it gets overwritten.
- command | tee -a output.txt The standard output stream will be copied to the file, it will still be visible in the terminal. If the file already exists, the new data will get appended to the end of the file.
- (*) Bash has no shorthand syntax that allows piping only StdErr to a second command, which would be needed here in combination with tee again to complete the table. If you really need something like that, please look at «How to pipe stderr, and not stdout?» on Stack Overflow for some ways how this can be done e.g. by swapping streams or using process substitution.
- command |& tee output.txt Both the standard output and standard error streams will be copied to the file while still being visible in the terminal. If the file already exists, it gets overwritten.
- command |& tee -a output.txt Both the standard output and standard error streams will be copied to the file while still being visible in the terminal. If the file already exists, the new data will get appended to the end of the file.
Redirect all output to file in Bash [duplicate]
I know that in Linux, to redirect output from the screen to a file, I can either use the > or tee . However, I’m not sure why part of the output is still output to the screen and not written to the file. Is there a way to redirect all output to file?
9 Answers 9
That part is written to stderr, use 2> to redirect it. For example:
foo > stdout.txt 2> stderr.txt or if you want in same file:
Note: this works in (ba)sh, check your shell for proper syntax
well, i found the reference and have deleted my post for having incorrect information. from the bash manual: ‘»ls 2>&1 > dirlist» directs only the standard output to dirlist, because the standard error was duplicated from the standard output before the standard output was redirected to dirlist» 🙂
also from the bash man «There are two formats for redirecting standard output and standard error: &>word and >&word Of the two forms, the first is preferred. This is semantically equivalent to >word 2>&1»
Two important addenda: If you want to pipe both stdout and stderr, you have to write the redirections in the opposite order from what works for files, cmd1 2>&1 | cmd2 ; putting the 2>&1 after the | will redirect stderr for cmd2 instead. If both stdout and stderr are redirected, a program can still access the terminal (if any) by opening /dev/tty ; this is normally done only for password prompts (e.g. by ssh ). If you need to redirect that too, the shell cannot help you, but expect can.
All POSIX operating systems have 3 streams: stdin, stdout, and stderr. stdin is the input, which can accept the stdout or stderr. stdout is the primary output, which is redirected with > , >> , or | . stderr is the error output, which is handled separately so that any exceptions do not get passed to a command or written to a file that it might break; normally, this is sent to a log of some kind, or dumped directly, even when the stdout is redirected. To redirect both to the same place, use:
EDIT: thanks to Zack for pointing out that the above solution is not portable—use instead:
If you want to silence the error, do:
How to record all outputs of Linux terminal to a file
For SQL Editors there is a spool command to record all outputs and activities. I would want the same functionality for linux terminal. All the command inputs and outputs typed on the terminal should be recorded into a file, while the output provided should also be available on the stdout of the console that I am using.
2 Answers 2
This is a job for script (comes with bsdutils ).
You can start a script enabled terminal session by:
If you do not provide any filename to save the terminal contents, all outputs will be saved in a typescript file in the directory from where script is invoked.
note that script capture all the characters generated, including Ctrl chars like line ending Ctrl-J (maybe as ^J ). If you need to show this to non-techies, allow extra time to clean up the out_file 😉 Good luck.
The easiest and simplest way of only recording output of a command in Linux terminal is to use the redirection operators i.e ‘>’
Lets say we want to record ls -alt commands output in a file. so the command would be :
this will create a file output.txt and write the output to it, if file already exists then it will overwrite that file, (existing information wil be gone)
In case you want to append the output to an existing file the use ‘>>’ instead :
This will create or append to a file in case it is already there.
To record output as well as print it on stdout the command should be
This rdirects your output to file as well as stdout
If you want botn stdout and stderr then you have redirect and combine them using the 2>&1 command, which will look like :
Here 2 is the file descriptor for stderr and 1 is stdout ( stdin fd is 0), so we are redirecting and combining stderr with stdout because only stdout can be piped.
More information can be found in here
How do I capture all of my compiler’s output to a file?
While compiling I’m getting lot of compiler warnings. I want to start fixing them. My question is how to capture all the compiler output in a file? $make > file is not doing the job. It’s just saving the compiler command like g++ -someoptions /asdf/xyz.cpp I want the output of these command executions.
Best practice recommended by the autoconf maintainers is to execute your first command differently: use ‘../trunk configure CFLAGS=»-g Wall» CXXFLAGS=»-g Wall» . ‘. That is, don’t set C
@William Pursell, I believe pecker is, the ‘$’ dollar sign I believe is being used to represent the shell prompt, due to the its usage on the second line ($make), simply without the typically space after the shell prompt.
@mctylr «$ FOO=x cmd» is very different from «$ cmd FOO=x». In the former, cmd is run with FOO set to «x» in the environment. In the latter, the string «FOO=x» is an argument to cmd.
11 Answers 11
The compiler warnings happen on stderr , not stdout , which is why you don’t see them when you just redirect make somewhere else. Instead, try this if you’re using Bash:
The & means «redirect stdout and stderr to this location». Other shells often have similar constructs.
Please note that >&, &> and 2>&1 are all shell dependent, and may work or not depending on if you have bash/csh or other shells. @Alberto: I was confused too, because I was using csh and &> didn’t work for me while >& worked. This was the reason.
I.e. > redirects stdout, 2>&1 redirects stderr to the same place as stdout
Lots of good answers so far. Here’s a frill:
$ make 2>&1 | tee filetokeepitin.txt will let you watch the output scroll past.
I think that the return code of a pipeline is usually the return code of the last command; in this case, tee not make . So the || more unfortunately doesn’t do what you say it does. Compare false || echo $? to false | cat || echo $? .
@ephemient: Ah. You are right. heck, I made that work once, and now I can’t recall how. In anycase, I use tee in this application fairly often.
The output went to stderr. Use 2> to capture that.
Assume you want to hilight warning and error from build ouput:
make |& grep -E "warning|error" While code-only answers are not forbidden, please understand that this is a Q&A community, rather than a crowd-sourcing one, and that, usually, if the OP understood the code being posted as an answer, he/she would have come up with a similar solution on his/her own, and wouldn’t have posted a question in the first place. As such, please provide context to your answer and/or code by explaining how and/or why it works.
Based on an earlier reply by @dmckee
This gives you real-time scrolling output while compiling, and simultaneously write to the makelog.txt file.
Try make 2> file . Compiler warnings come out on the standard error stream, not the standard output stream. If my suggestion doesn’t work, check your shell manual for how to divert standard error.
The > character does not redirect the standard error. It’s useful when you want to save legitimate output without mucking up a file with error messages. But what if the error messages are what you want to save? This is quite common during troubleshooting. The solution is to use a greater-than sign followed by an ampersand. (This construct works in almost every modern UNIX shell.) It redirects both the standard output and the standard error. For instance:
$ gcc invinitjig.c >& error-msg Have a look there, if this helps: another forum