ek@Io:~/source$ ls -l hello
-rwxrwxr-x 1 ek ek 9608 Jan 26 2017 hello
ek@Io:~/source$ ./hello
Hello, world!
ek@Io:~/source$ chmod -x hello
ek@Io:~/source$ ls -l hello
-rw-rw-r-- 1 ek ek 9608 Jan 26 2017 hello
ek@Io:~/source$ ./hello
-bash: ./hello: Permission denied
ek@Io:~/source$ file hello
hello: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, for GNU/Linux 2.6.32, BuildID[sha1]=ab9d2c6c31cac5bb10d976ea354673e7f3c6ea66, not stripped