Can I move to a previous line in shell script?

[sky_knight02]

echo "line 1"
echo "line 2'
[output]
line 1
line 2


Question: Can i move to line 1 and change '1' to '3' without damaging the line 2?

[dxqcanada]

Is this a question about how to use a specific text editor ?

[sky_knight02]

I want to print in the line 1 again without damaging line 2 in a shell script in console or terminal

[Freston]

Interesting question. I wouldn't know. Usually I clear the screen and start anew. It works.

Something like this:

VAR1="1"
VAR2="2"

ShowOutput () {
clear
cat << EOF
$VAR1
$VAR2
EOF
}

SimpleLoop () {
while true ; do
echo -n "What do you want as first variable? "
read -n 1 VAR1
ShowOutput
done
}

SimpleLoop

[sky_knight02]

Very nice.... thanks...

But this is not im looking for...

Consider a wave motion starting in first line and moving to second line and again first line and again second line like wise...........
example:
\ /\ /\
V V
Like this wave motion... starting from first line and going to second and then move to first line again and again second, first etc..etc.........

I Think i can make this with your method but im not sure about it, i want to spend little time with it to be conformed. And also i want to know that whether is there any command or simple method to move to the previous line

thanks for your reply.......

[sky_knight02]

Very nice.... thanks...

But this is not im looking for...

Consider a wave motion starting in first line and moving to second line and again first line and again second line like wise...........
example:

\ /\ /\
V V

Like this wave motion... starting from first line and going to second and then move to first line again and again second, first etc..etc.........

I Think i can make this with your method but im not sure about it, i want to spend little time with it to be conformed. And also i want to know that whether is there any command or simple method to move to the previous line

thanks for your reply.......

[sky_knight02]

Can you please tell me the role of `cat << EOF and EOF here, I dont know what they are and why they are used for.

[Freston]

Can you please tell me the role of `cat << EOF and EOF here

When you want to output multiple lines, the cat OEF combo gives a cleaner look in the script and is easier when you want to insert lines, that's all. You could also put 'echo' on every line. It's the same.


As for what you want, well it's possible. Is it a repeating patern or a progressive pattern?

Repeating is very easy, just alternate between two different values in the variable.

If you want a progressive pattern, sort of like a character moving, then you need to put some effort in structuring it (hint: it's all about counting)

#!/bin/bash
opt="x"
alt="0"
var="0"
while [ "$alt" -le "11" ] ; do
	while [ "$var" -le "10" ] ; do
		var=`expr $var + 1`
		if [ "$alt" -eq "$var" ] ; then
			opt="X"
		else
			opt="x"
		fi
		echo -n $opt
	done
var="0"
alt=`expr $alt + 1`
sleep 0.2
clear
done

This will get you a moving X in a row of x's. Not particularly useful I'm afraid. But it is how I would get movement in a standard bash script output.

If you make it too big, then refresh rate gets a problem. So if anyone knows the answer to your original question? I bet there are better ways to do this.

[sky_knight02]

Thanks Freston.... this helped me a lot... ill let you know when i find it....

I hope some one will reply with the right answer.....

[drl]

Hi.

It sounds like you want to move the cursor.

One way to move the cursor around is to use tput. See Discover tput or Google for tput topics ... cheers, drl