get the cursor position in bash script

English Programming/Scripting
#1

Hi,

Is there a way to get the current cursor position in a bash script? I know that the positon can be saved and restored, but did not find a way to red the row and column values of where the cursor is.

#2

Don’t know if this helps you, it does not ‘get’ it, but ‘sets’ it:


tput cup 10 20

would move the cursor to row 10, column 20

‘man tput’ will give you more options.

#3

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Scripts do not have cursors. :slight_smile: They have lines and positions, but
usually those are clear when an error happens.

What is the point of this exercise? Wanting to know where something
breaks? You can get a lot of debugging data by loading the script
(assuming you mean bash since you don’t say otherwise) by running it as
follows:

bash -x /path/to/your/script.sh

If you mess up something completely, even without the ‘-x’ option, you
still get a line number for your failure:

…/test.sh: line 4: fakeCommand: command not found

If you are using a text editor in a file then the text editor may tell you
where you are, but that’s not what you asked and it would vary per editor
so more data are needed.

Good luck.

On 03/02/2010 05:56 AM, inp3dance wrote:
>
> Hi,
>
> Is there a way to get the current cursor position in a bash script? I
> know that the positon can be saved and restored, but did not find a way
> to red the row and column values of where the cursor is.
>
>
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#4

Must disagree, see example:


tput cup 100 100; read TXT; tput cup 100 101; echo $TXT

This will put the cursor at row 100, column 100, read input, and echo input one line beneath.

The command was explained to me in the late eighties as meaning ‘terminal put cursor position rownumber columnnumber’. I’ve used these kind of scripts for ages.

#5

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Yes, true… I misunderstood the question, or understood it based only on
text and not on what was desired. This does not put the cursor anywhere
in the script, but rather puts the cursor somewhere within the terminal
based on code within the script. Anyway, I imagine your interpretation of
the question was correct and mine was not.

Good luck.

On 03/02/2010 06:46 AM, Knurpht wrote:
>
> ab@novell.com;2129345 Wrote:
>> Scripts do not have cursors. :slight_smile: They have lines and positions, but
>> usually those are clear when an error happens.
>>
>>
>
> Must disagree, see example:
>
>
> Code:
> --------------------
>
> tput cup 100 100; read TXT; tput cup 100 101; echo $TXT
>
> --------------------
>
>
>
> This will put the cursor at row 100, column 100, read input, and echo
> input one line beneath.
>
> The command was explained to me in the late eighties as meaning
> ‘terminal put cursor position rownumber columnnumber’. I’ve used these
> kind of scripts for ages.
>
>
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#6

I needed to get the current row and column value because I was working on some kind of progress bar in bash. But resolved other way, if somebody need to inspire, here it is ( critique is welcome too ):


#!/bin/bash

function progress_bar_init	
{
    # get the number of columnss
    cols=$(tput cols)
    
    #number of columns in the progress bar_cols
    # will be like this:  ========                  ] xxx%
    bar_cols=$$cols-8]

    max_bar_cols=100
    if  $bar_cols -gt $max_bar_cols ]; then
	bar_cols=$max_bar_cols
    fi

    #draw the empty progress bar
    echo -n ""
    tput cuf $bar_cols
    echo -n "] 0%"

    current_position=0
    characters=1
}

function progress_bar
{
    p=$1
    #calculate the position to go in the progress_bar
    position=$$bar_cols*$p/100]
    
    if  "$position" -gt "$bar_cols" ]; then
	position=$bar_cols
    fi

    #go to the current position 
    tput cub $$bar_cols+3+$characters-$current_position]
    
    #full up from current position to new position
    for ((f=0;f<$$position-$current_position];f+=1)); do
	echo -n "="
    done
    
    #update the current position
    current_position=$position

    #write the precentage value at the end
    tput cuf $$bar_cols-$position+2]
    echo -n $p"%"

    if  "$p" -gt "9" ]; then
	characters=2
    fi

    if  "$p" -gt "99" ]; then
	characters=3
    fi
    
}

progress_bar_init

for ((i=0;i<=120;i+=3)); do
    progress_bar $i
    sleep 0.5
done
#7

And yes, the question was not defined right. What I was asking is to get the cursor position on the terminal, not in the editor, my mistake, sorry.

#8

Pixel graphics or character cell graphics? If the latter, have a look at ncurses.

#9

ANSI sequences: when you send **<ESC>[6n[/b] to the screen it returns an escape sequence with the cursor position: <ESC>{ROW};{COLUMN}R

See: ANSI Standard (X3.64) Control Sequences for Video Terminals and Peripherals**

#10

Thank you vodoo, just another one question: if I do echo -e “\0336n”, how can I read the response for that?