Red Hat ENTERPRISE LINUX 4 - DEVELOPER TOOLS GUIDE, Manual

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28 Chapter 6. Running Programs Under gdb
tells the debugged program, when subsequently run, that its user is named
foo
. (The spaces
around
=
are used for clarity here; they are not actually required.)
unset environment
varname
Remove variable
varname
from the environment to be passed to your program. This is different
from
set env
varname
=
;
unset environment
removes the variable from the environment,
rather than assigning it an empty value.
Warning: On Unix systems, gdb runs your program using the shell indicated by your
SHELL
envi-
ronment variable if it exists (or
/bin/sh
if not). If your
SHELL
variable names a shell that runs an
initialization file--such as
.cshrc
for C-shell, or
.bashrc
for BASH--any variables you set in that
file affect your program. You may wish to move setting of environment variables to files that are only
run when you sign on, such as
.login
or
.profile
.
6.5. Your program’s working directory
Each time you start your program with
run
, it inherits its working directory from the current working
directory of gdb. The gdb working directory is initially whatever it inherited from its parent process
(typically the shell), but you can specify a new working directory in gdb with the
cd
command.
The gdb working directory also serves as a default for the commands that specify files for gdb to
operate on. Refer to Section 17.1 Commands to specify files .
cd
directory
Set the gdb working directory to
directory
.
pwd
Print the gdb working directory.
6.6. Your program’s input and output
By default, the program you run under gdb does input and output to the same terminal that gdb uses.
gdb switches the terminal to its own terminal modes to interact with you, but it records the terminal
modes your program was using and switches back to them when you continue running your program.
info terminal
Displays information recorded by gdb about the terminal modes your program is using.
You can redirect your program’s input and/or output using shell redirection with the
run
command.
For example,
run outfile
starts your program, diverting its output to the file
outfile
.
Another way to specify where your program should do input and output is with the
tty
command.
This command accepts a file name as argument, and causes this file to be the default for future
run
commands. It also resets the controlling terminal for the child process, for future
run
commands. For
example,