ldconfig

About

ldconfig is a tool to configure the dynamically assigned runtime libraries under /usr/lib and /usr/local/lib or other ad-hoc locations.

Uses

Print the current cache

$ ldconfig -p

Look for a linked library

 /sbin/ldconfig -v

 /sbin/ldconfig -v | grep gdal

for example

Troubleshooting

If you have just installed something, and it find it doesn't run or spits out missing library type errors, there is a good chance the install didn't run ldconfig. You can manually link libraries by passing them as command line arguments with the -l switch:

$ ldconfig -l /usr/local/lib/foo.so

Or alternatively, add your library path to /etc/ld.so.conf or include it in a file under /etc/ld.so.conf.d/ and run ldconfig to update the cache: