[Techtalk] wvdial, pppd, and permissions insanity- solved!!!

[Magni Onsoien]

On 2005-10-14 17:23:08 -0700, Carla Schroder said:

> SHRIEK OMG you are my hero and a genius and everything. It was lockfile perms- 
> on CentOS they were drwxrwxr-t. I changed 'em and now it all works it works 
> it works *passes out*

I have found strace(1) very useful for finding out what a piece of
software is actually trying to do when regards to reading config files
and writing stuff all over the place.

'strace -eopen' will show all the files the program ever tries to open,
including libraries the program uses, logfiles, configfiles etc.

strace has a lot of options, and is really useful for all kinds of
diagnostics and debugging (as long as you don't get into a heisenbug[1],
that is...) - or just for fun and learning. 

You just start the command line with 'strace' and its options, then put 
the regular command you want to trace, with all its options, at the end. 
Forgot to use strace? Just use -p<pid> to attach to the process.

strace is available for Linux, SysV, SunOS, Irix and Solaris.
The half-sister of strace for FreeBSD (and probably the other BSDs) is
ktrace; not quite the same, but close enough for many purposes. Unlike
strace it won't write to stderr, but to a file - use kdump to read the
file. On some Solaris/SunOS systems you will find strace, but the usual
tool (the one that comes from the vendor, I think) is 'truss'.


Magni :)


[1] http://www.hacker-dictionary.com/terms/heisenbug
-- 
sash is very good for you.