Unix Tip: Using stty to Your Advantage

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The stty (set the options for a terminal) command can be very useful once you get the knack of using it. Stty can give you quick manual control over the characteristics of your terminal. If ever you have found yourself working on a terminal in which the terminal settings did not match your actual terminal, you will know how annoying this situation can be. It is often experienced when you attempt to backspace to fix a typo on the command line and, instead of seeing the cursor move backwards on the line erasing characters, you see an increasingly long string of ^H or ^? characters appearing at the end of your command line.

boson> echo "Please send me the lsit^H^H^H

What this tells you is that ^H (control-H) is not functioning as an erase. Using stty, however, you can reset your erase character like this:

boson> stty erase \^h



To see a list of your current stty settings, type the following command:

stty -a



This command will list your current settings in a format like this:

boson> stty -a

speed 38400 baud;

rows = 80; columns = 132; ypixels = 0; xpixels = 0;

csdata ?

eucw 1:0:0:0, scrw 1:0:0:0

intr = ^c; quit = ^\; erase = ^h; kill = ^u;

eof = ^d; eol = <<undef> eol2 = <undef> swtch = <undef>

start = ^q; stop = ^s; susp = ^z; dsusp = ^y;

rprnt = ^r; flush = ^o; werase = ^w; lnext = ^v;

-parenb -parodd cs8 -cstopb -hupcl cread -clocal -loblk -crtscts -crtsxoff -parext

-ignbrk brkint -ignpar -parmrk -inpck -istrip -inlcr -igncr icrnl -iuclc

ixon -ixany -ixoff imaxbel

isig icanon -xcase echo echoe echok -echonl -noflsh

-tostop echoctl -echoprt echoke -defecho -flusho -pendin iexten

opost -olcuc onlcr -ocrnl -onocr -onlret -ofill -ofdel tab3

The standard control characters are:

control-d end of file (eof)

control-h backspace (erase)

control-z suspend (susp)

control-u delete text from start of line (kill)

control-c interrupt

The most commonly used stty command is undoubtedly the "stty erase ^h" command which is often used in scripts

if [ `tty | grep -ci console` -eq 0 ]
then
	stty ERASE ^H
	TERM=SUN
fi

You can also display your settings in a format which allows you to restore them at a later time. This is done with the "stty -g" command, the output of which (on one of my Solaris systems) looks like this:

boson> stty -g

2502:1805:f00bf:8a3b:17:1c:7f:15:4:0:0:0:11:13:1a:19:12:f:17:16:0:0:1:1:0:00:0

:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0

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