Imported from ../bash-2.04.tar.gz.
This commit is contained in:
Jari Aalto
185
examples/scripts/line-input.bash
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185
examples/scripts/line-input.bash
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#! /bin/bash
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#
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#From: kaz@cafe.net (Kaz Kylheku)
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#Newsgroups: comp.unix.shell
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#Subject: Funky little bash script
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#Message-ID: <6mspb9$ft2@espresso.cafe.net>
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#Date: Thu, 25 Jun 1998 06:11:39 GMT
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#Here is something I wrote a few years ago when I was bored one day.
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#Warning: this contains control characters.
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# Line input routine for GNU Bourne-Again Shell
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# plus terminal-control primitives.
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#
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# by Kaz Kylheku
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# June 1996, Vancouver, Canada
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#
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# Function to disable canonical input processing.
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# Terminal modes are saved into variable "savetty"
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#
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#
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function raw
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{
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savetty=$(stty -g)
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stty -icanon -isig -echo -echok -echonl inlcr
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}
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#
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# Function to restore terminal settings from savetty variable
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#
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function restore
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{
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stty $savetty
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}
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#
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# Set terminal MIN and TIME values.
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# If the input argument is a zero, set up terminal to wait for
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# a keystroke indefinitely. If the argument is non-zero, set up
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# an absolute timeout of that many tenths of a second. The inter-keystroke
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# timer facility of the terminal driver is not exploited.
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#
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function settimeout
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# $1 = tenths of a second
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{
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if [ "$1" = "0" ] ; then
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min=1
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timeout=0
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else
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min=0
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timeout="$1"
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fi
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stty min $min time $timeout
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unset min timeout
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}
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#
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# Input a single key using 'dd' and echo it to standard output.
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# Launching an external program to get a single keystroke is a bit
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# of a pig, but it's the best you can do! Maybe we could convince the
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# GNU guys to make 'dd' a bash builtin.
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#
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function getkey
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{
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eval $1="\"\$(dd bs=1 count=1 2> /dev/null)\""
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}
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#
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# Input a line of text gracefully.
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# The first argument is the name of a variable where the input line is
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# to be stored. If this variable is not empty, its contents are printed
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# and treated as though the user had entered them.
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# The second argument gives the maximum length of the input line; if it
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# is zero, the input is unlimited (bad idea).
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# ^W is used to delete words
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# ^R redraws the line at any time by backspacing over it and reprinting it
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# ^U backspaces to the beginning
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# ^H or ^? (backspace or del) delete a single character
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# ^M (enter) terminates the input
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# all other control keys are ignored and cause a beep when pressed
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#
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#
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function getline
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{
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settimeout 0 # No keystroke timeout.
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save_IFS="$IFS" # Save word delimiter and set it to
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IFS="" # to null so ${#line} works correctly.
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eval line=\${$1} # Fetch line contents
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echo -n "$line" # and print the existing line.
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while [ 1 ] ; do
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getkey key # fetch a single keystroke
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case "$key" in
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| ) # BS or DEL
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if [ ${#line} != 0 ] ; then # if line not empty
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echo -n " " # print destructive BS
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line="${line%%?}" # chop last character
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else # else if line empty
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echo -n # beep the terminal
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fi
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;;
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) # kill to line beg
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while [ ${#line} != 0 ] ; do # while line not empty
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echo -n " " # print BS, space, BS
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line="${line%?}" # shorten line by 1
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done
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;;
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) # redraw line
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linesave="$line" # save the contents
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while [ ${#line} != 0 ] ; do # kill to line beg
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echo -n " "
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line="${line%?}"
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done
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echo -n "$linesave" # reprint, restore
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line="$linesave"
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unset linesave # forget temp var
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;;
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)
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while [ "${line% }" != "$line" -a ${#line} != 0 ] ; do
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echo -n " "
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line="${line%?}"
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done
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while [ "${line% }" = "$line" -a ${#line} != 0 ] ; do
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echo -n " "
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line="${line%?}"
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done
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;;
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| | | | | | | | | | |
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)
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echo -n # ignore various control characters
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;; # with an annoying beep
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| | | | | | | | | | | | )
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echo -n
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;;
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' ' | | | | | )
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echo -n
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;;
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'' ) # Break out of loop on carriage return.
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echo # Send a newline to the terminal.
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break # (Also triggered by NUL char!).
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;;
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* ) # Append character to the end of the line.
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# If length is restricted, and the line is too
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# long, then beep...
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if [ "$2" != 0 -a $(( ${#line} >= $2 )) = 1 ] ; then
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echo -n
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else # Otherwise add
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line="$line$key" # the character.
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echo -n "$key" # And echo it.
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fi
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;;
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esac
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done
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eval $1=\"\$line\"
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IFS="$save_IFS"
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unset line save_IFS
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}
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# uncomment the lines below to create a standalone test program
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#
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echo "Line input demo for the GNU Bourne-Again Shell."
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echo "Hacked by Kaz Kylheku"
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echo
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echo "Use ^H/Backspace/Del to erase, ^W to kill words, ^U to kill the"
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echo "whole line of input, ^R to redraw the line."
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echo "Pass an argument to this program to prime the buffer contents"
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raw
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echo -n "go: "
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if [ ${#1} != 0 ] ; then
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LINE=$1
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fi
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getline LINE 50
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restore
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echo "<$LINE>"
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