9.3 Editing Source Files

To edit the lines in a source file, use the edit command. The editing program of your choice is invoked with the current line set to the active line in the program. Alternatively, there are several ways to specify what part of the file you want to print if you want to see other parts of the program:

edit locspec

Edit the source file of the code location that results from resolving locspec. Editing starts at the source file and source line locspec resolves to. See Location Specifications, for all the possible forms of the locspec argument.

If locspec resolves to more than one source line in your program, then the command prints the list of resolved source lines and does not proceed with the editing.

Here are the forms of the edit command most commonly used:

edit number

Edit the current source file with number as the active line number.

edit function

Edit the file containing function at the beginning of its definition.

9.3.1 Choosing your Editor

You can customize GDB to use any editor you want ¹⁰. By default, it is /bin/ex, but you can change this by setting the environment variable EDITOR before using GDB. For example, to configure GDB to use the vi editor, you could use these commands with the sh shell:

EDITOR=/usr/bin/vi
export EDITOR
gdb …

or in the csh shell,

setenv EDITOR /usr/bin/vi
gdb …

ex +number file