How to attach a process in gdb

The first argument should be the path to the executable program. So

gdb progname 12271

Try one of these:

gdb -p 12271
gdb /path/to/exe 12271

gdb /path/to/exe
(gdb) attach 12271

With a running instance of myExecutableName having a PID 15073:

hitting Tab twice after $ gdb myExecu in the command line, will automagically autocompletes to:

$ gdb myExecutableName 15073

and will attach gdb to this process. That's nice!

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