how to catch the warning/error messages on the screen

[Reggie Chang]

Hello there,

When I run script files (or makefiles), sometimes I got warning/error messages on the screen. How to catch those messages? I tried
to use '>' and '>>' to direct a file but it
did not work.

The info is very much appreciated.

Reggie

[A. Clay Stephenson]

By convention, those do not go to stdout but rather to stderr.

Suppose that your command/script is called myfile.sh,

myfile.sh > mylogfile 2>myerrfile

That would output the normal messages (stdout) to mylogfile and the errors (stderr) to myerrfile.

If all you want are the errors,
myfile.sh 2>myerrfile.

If you want to send both stdout and stderr to the same file:

myfile.sh > mylogfile 2>&1

Regards, Clay

[Luc Bussieres]

Hi,

If you are using the default shell to redirect the standard error also you should use 2> filename or 2>&1 to redirect both in the same filename.

For example:

command > filename 2>&1
will redirect all output of command to the file name filename

and

command > filename 2> filename2
will redirect the standard output to filename and the error messages to filename2.

Luc

[Michael Tully · Accepted solution]

Hi,

If you wish to collect all messages that are displaying on your terminal screen you can use the script command. It will display all commands and output of these which display on your screen into a text file.

# script /tmp/myoutput
# command x
# command y
controlD to finish

HTH
-Michael