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1. Say command
This is an interesting command: Say converts text to speech using the text-to-speech system used by voiceover in OS X. Without any options, the say command translates any text content you enter into speech output:
$ say "Never trust a computer you can ' t lift."
You can use the say command with the-f flag to read the contents of a text document while using the-O identity to save the output's audio content:
$ say-f Mynovel.txt-o Myaudiobook.aiff
The say command can be used for script console logs and alarm sounds. For example, you can set up batches or hazel scripts to process files and use the say command to issue reminders after processing is complete.
But the best way to play with the say command is sinister: if you have SSH access to your friend or colleague's Mac, you can log on to their computer silently via the command line. Then give them a siri-ous surprise.
You can set the voice (and language) of the say command in the Dictation and speech panel in System Preferences.
Mac Command Daquan