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making a .sh wait for user input


 
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# 8  
Old 01-21-2004
Don't apologize. There is nothing wrong with posting a followup to an old thread. The only problem is it would take a book to really answer your question. I'll take a shot at a summary.

The tty driver controls how input lines that you type are delivered to programs. Normally a tty driver will wait until a complete line is available. It also handles stuff like backspace so that program doesn'y need to. The stty command lets you change the way the tty driver works. "stty -a" will display all of the settings. You should do that to see what's available.

"stty -g" displays all of the settings too. But it's encoded and you can't understand the output. But you can save the output and feed it back into the stty command. So:
oldtty=`stty -g`
stty $oldstty
will save and restore the original settings of the tty driver.

stty -canon -echo min 1 time 0
is setting some options in the tty driver. -icanon turns off all special character processing. Now a backspace will be passed to the program rather than being processed. And a carriage return won't terminate a line. So now min and time control when a read has finished. "min 1" says we need at least one character. "time 0" means that we won't wait a while before completing a read. So each read from the program may return after just one character.

the -echo just turns off echo. I would not have done that.

dd is a program that is prepared to read data that is not organized into lines. This dd will read one block (count=1) of data. And that block will be one character in length (size=1). So the dd will read one character and return to the script.

The final echo moves the cursor to the next line.
# 9  
Old 01-21-2004
and i was just gonna say, i havnt seen livinfree post in a while...

Smilie
# 10  
Old 01-28-2004
Well thanks Perderabo!
That clears a lot of doubts I had regarding the script.

Thanks
 

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