How do I capture all of my compiler's output to a file?

Question

Hello,

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 to a file?

$make > file is not doing the job. Its just saving the the compiler command like g++ -someoptions /asdf/xyz.cpp I want the output of these command executions.

Answer 1

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.

Answer 2

In a bourne shell:

make > my.log 2>&1

I.e. > redirects stdout, 2>&1 redirects stderr to the same place as stdout

Answer 3

The output went to stderr. Use 2> to capture that.

$make 2> file

Answer 4

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:

$make &> results.txt

The & means "redirect stdout and stderr to this location".

Answer 5

Lots of good answers so far. Here's a frill:

$ make 2>&1 | tee filetokeepitin.txt 

will let you watch the output scroll past.

Answer 6

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