Just do bash file:
bash file
$ cat file dateecho '12*12' | bc$ bash fileMon Nov 26 15:34:00 GMT 2012144
In case of aliases just run bash -i file
bash -i file
No need to worry about file extensions or execution rights.
In a Terminal just type:
bash path/to/my/file.txt
And you will get each lines executed.
just change the extension of the file to .sh
add /bin/bash at starting of the file
change the permission of the file to executable
than simply run ./filename.sh command in command line. all the commands in the file will be executed