Find info about linux app file

Question

I have a program I want to run in debian but when I start it I get a segmentation fault error. It has worked before in debian. Are there any commands I can run to see what the problem can be? What libs it needs and if it's a valid executable at all?

Answer 1

strace or gdb. Strace will print system calls trace, gdb program allows to type bt after crash and see the stack trace.

Answer 2

For a start type

whereis programname

to obtain the location of the executable, its documentation, and (possibly) its source code on your system. Then type

file `which programname`

to see if it is a valid executable. Then type

/lib/ld-linux.so.* --list `which programname`

to see the shared libraries the program requires to run.

Finally, type

ulimit -c unlimited
programname
gdb `which programname` core
where
q

to obtain the precise location of the crash.

Example:

$ whereis perl
perl: /usr/bin/perl /usr/bin/X11/perl /usr/share/man/man1/perl.1.gz

$ file `which perl`
/usr/bin/perl: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), for GNU/Linux 2.6.4, dynamically linked (uses shared libs), stripped

$ /lib/ld-linux.so.* --list `which perl`
        linux-gate.so.1 =>  (0xffffe000)
        libnsl.so.1 => /lib/libnsl.so.1 (0xb7f56000)
        libdl.so.2 => /lib/libdl.so.2 (0xb7f51000)
        libm.so.6 => /lib/libm.so.6 (0xb7f28000)
        libcrypt.so.1 => /lib/libcrypt.so.1 (0xb7ef1000)
        libutil.so.1 => /lib/libutil.so.1 (0xb7eec000)
        libpthread.so.0 => /lib/libpthread.so.0 (0xb7ed2000)
        libc.so.6 => /lib/libc.so.6 (0xb7d76000)
        /lib/ld-linux.so.2 (0xb7f92000)

$ ulimit -c unlimited
$ perl
^\Quit (core dumped)
$ gdb `which perl` core
GNU gdb (GDB; openSUSE 11.1) 6.8.50.20081120-cvs
Copyright (C) 2008 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html&gt;
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "i586-suse-linux".
For bug reporting instructions, please see:
<http://bugs.opensuse.org/&gt;...
(no debugging symbols found)
Core was generated by `perl'.
Program terminated with signal 3, Quit.
#0  0xffffe430 in __kernel_vsyscall ()
(gdb) where
#0  0xffffe430 in __kernel_vsyscall ()
#1  0xb7fd2b93 in __read_nocancel () from /lib/libpthread.so.0
#2  0x081bcb9b in PerlIOUnix_read ()
#3  0x081be025 in PerlIOBuf_fill ()
#4  0x081bc402 in PerlIOBase_read ()
#5  0x081bc571 in PerlIO_getc ()
#6  0x0812121e in Perl_sv_gets ()
#7  0x081f11e1 in Perl_filter_read ()
#8  0x081f15e3 in ?? ()
#9  0x081facc9 in Perl_yylex ()
#10 0x08210674 in Perl_yyparse ()
#11 0x080d844f in ?? ()
#12 0x080dc372 in perl_parse ()
#13 0x08063ff8 in main ()
(gdb) quit

Example: