Compile linux .a and .so file

Compile linux .a and .so file

now, I got main.c, sub.h, sub.c, util.h, util.c.

how to compile main.bin?
#gcc -o main.bin *.c

how to compile sub.a?
#gcc -c -o sub.o sub.c
#ar r sub.a sub.o

how to compile sub.so?
 #gcc -fpic -c -o sub.o sub.c
#gcc -shared -o sub.so sub.o

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