How to find the library type (.so or .a) in C++/UNIX

Question

Given a C++/UNIX library file (without extension), i need to determine the type of library whether it is a dynamic library (.so file) or a static library (.a file) based on its content (say grepping the content against a keyword)

How do i do it in UNIX command line ?

Answer 1

Tryfile <library name>. It should displayshared or dynamically linked among its output if the file is a dynamically loadable module.

Answer 2

Try file -L <library name> | grep shared if this produces any output, the file is dynamically linked. Alternately you could do ldd <library name> | grep 'not a dynamic executable' which produces output if it's static. Hope this answers your question, I would have added a comment to Aviator's answer, but I cannot comment (yet).

The -L option to file forces files to dereference symlinks, which is not the default behavior if POSIXLY_CORRECT is not defined (as it is the case on my system).

Script example:

if [ -z "$(file -L  | grep shared)" ]; then
    echo "not a dynamic lib";
else
    echo "dynamic lib";