I'm building an opensource project from source (CPP) in Linux. This is the order:
$CFLAGS="-g Wall" CXXFLAGS="-g Wall" ../trunk/configure --prefix=/somepath/ --host=i386-pc --target=i386-pc
$make
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.
This question is related to
linux
shell
g++
makefile
io-redirection
Assume you want to hilight warning and error from build ouput:
make |& grep -E "warning|error"
Lots of good answers so far. Here's a frill:
$ make 2>&1 | tee filetokeepitin.txt
will let you watch the output scroll past.
From http://www.oreillynet.com/linux/cmd/cmd.csp?path=g/gcc
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
In a bourne shell:
make > my.log 2>&1
I.e. > redirects stdout, 2>&1 redirects stderr to the same place as stdout
In C shell - The ampersand is after the greater-than symbol
make >& filename
The output went to stderr. Use 2> to capture that.
$make 2> file
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:
$ make &> results.txt
The & means "redirect stdout and stderr to this location". Other shells often have similar constructs.
It is typically not what you want to do. You want to run your compilation in an editor that has support for reading the output of the compiler and going to the file/line char that has the problems. It works in all editors worth considering. Here is the emacs setup:
https://www.gnu.org/software/emacs/manual/html_node/emacs/Compilation.html
Based on an earlier reply by @dmckee
make | tee makelog.txt
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.
Source: Stackoverflow.com