Hello, I am wondering how to write the null character in terminal?
Hello,
I have a MacBook pro laptop running lion.
I wondered how to write the null character in terminal text edit textwrangler etc.
echo $'\0'
8 replies
Hello,
Thanks for the response. I have an external speech synthesizer i am trying to test. I want to use the cat and echo command to send text out to my synthesizer.
I have a usb2serial adaptor, and its driver. So if i use the echo command how would i end a line of text with a null character?
Like if i type
echo testing, one, two, three $'/0'
Would terminal recognize the null character?
I am gonna try that now. Another thing sometimes i use the set command to set up communication with the synthesizer. Set speed 9600, set carrier-watch off etc. I am trying to test a synthesizer. I had it working awhile back. But cant remember the exact set-up that worked.
My goal right know is to use the cat and echo command, right a line of text ending with a nul character, redirect it to my usb2serial adaptor and hopefully have my synthesizer speak the line.
Anyway any further help would be great.
Like if i type
echo testing, one, two, three $'/0'
Would terminal recognize the null character?
No, because that's a forward slash, not a backslash. But every ASCII string is terminated by a null character, so it doesn't really matter.
Hello
When i type:
echo hello, i am talking $'\0' > /dev/**.usbserial-FTKVMAFF
In terminal i get no output from my speech synthesizer, but when i go into a text editor like text edit, or when i put a null character directly into the terminal from show character viewer. Which i enabled in system preferences. I get audio output.
So i am wondering if there is a way to enter a null character from my terminal keyboard? I think in the bash shell the only command line option is -n, which has something to do with a newline. In my notes i have written
echo -n -e
And i believe the -e is for the terminal to recognize special escape sequences. So i am going to try to open an sh shell and man the echo command.
Btw my synthesizer will also recognize the carriage return, would you happen to know how to produce that. I can get it from character viewer but am looking for a keyboard shortcut?
If you want to talk to a serial device, you need a serial comm program such as minicom. What you're trying to do won't work.
Then why when i put the null character in from the character viewer, it works. In other words i type
echo hello, i am talking
Then i drag a null character from viewer pallette. Then i type
> /dev/**.usbserial-FTKVMAFF
And i get audio output? I do have a usb2serial adaptor and its driver installed.
I'm sorry, but I can't debug your device for you. I've answered your original question. You also asked about a carriage return; that's ASCII code 13, so replace the 0 with that number.
From: http://superuser.com/questions/293260/how-can-i-write-the-null-character-on-a-ma cbook-pro
You can do this with the Unicode Hex Input method (enable it in System Preferences -> Language & Text pane -> Input Sources tab, then select it from the menu item) by holding Option and typing "0000".
Warning: the null character is not allowed in C-language strings (it's used to indicate the end of the string), so not all programs will cope with it. In TextEdit, for example, you can insert a null into a document, but when you save the document it'll only save the part before the null.
Hello, I am wondering how to write the null character in terminal?