gcc compilation process..

gcc -Iproj/src myfile.c -o myfile
gcc -c myfile.c "compile without linking
gcc -D DEBUG myfile.c -o myfile
gcc -glevel  "level=0,1,3,null
"gcc -l links with a library file.
"gcc -L looks in directory for library files. "Link -l with library name without the lib prefix and the .a or .so extensions
gcc myfile.c -o myfile
gcc -Wall  "enable all warnings..

gcc

-I -L -l -D -g -O -o -Wall

about the -0 option.. ref to the following table..

Set the compiler‘s optimization level.

+increase ++increase more +++increase even more -reduce --reduce more ---reduce even more