Eran Peled used the following line for compiling on my MACBOOK pro gcc main.c -o ls-linux -Wall; example for possible output: /Users/eran/Documents/ClionProjects/ls-ex1/cmake-build-debug/ls_ex1 README.txt The Output of /Users/eran/Documents/ClionProjects/ls-ex1/cmake-build-debug/README.txt is: -rw-r--r-- 1 eran staff 140 Apr 5 2017 README.txt Process finished with exit code 0 ———————————————————————————————————————————— /Users/eran/Documents/ClionProjects/ls-ex1/cmake-build-debug/ls_ex1 isPrimeRoni /Users/eran/Documents/ClionProjects/ls-ex1 The Output of /Users/eran/Documents/ClionProjects/ls-ex1/cmake-build-debug/isPrimeRoni is: -rwxr-xr-x 1 eran staff 8624 Apr 3 2017 isPrimeRoni The Output of /Users/eran/Documents/ClionProjects/ls-ex1 is: drwxr-xr-x 9 eran staff 306 Apr 5 2017 . drwxr-xr-x 5 eran staff 170 Apr 5 2017 .. -rw-r--r-- 1 eran staff 6148 Apr 4 2017 .DS_Store drwxr-xr-x 7 eran staff 238 Apr 5 2017 .idea drwxr-xr-x 14 eran staff 476 Apr 5 2017 cmake-build-debug -rw-r--r-- 1 eran staff 201 Apr 5 2017 CMakeLists.txt -rwxr-xr-x 1 eran staff 13940 Apr 5 2017 ls-linux -rw-r--r-- 1 eran staff 4839 Apr 5 2017 main.c -rw-r--r-- 1 eran staff 537 Apr 5 2017 README.txt Process finished with exit code 0 ————————————————————————————————————————————————————————————— enjoy.