[Bash Shell Scripting] Update echoed lines?

[codemaniac]

Hello!

I am stuck in my Bash script again, this time I need to do something complex; I want to echo a line and then after 1 second "modify" the previous line to something else.

Here's a GIF of what I want to do (I did it in GIMP):

(Ofcourse I don't want it to loop, but I want to increment the number in the end of the last line and update the string after 1 second.)

A simple approach would be to clear the screen and print everything again, but that's too lame and a little slow if there's lots of content to clear and echo again.. Can anyone help me? Thanks!

[WishMaster]

Voilà:

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echo -en "Please wait, i'll be overwritten soon"\\\r; sleep 2; echo -en "Hello, I'm the new text... (oh, and I must be longer than the one before or have some spaces at the end)" \\n 

[codemaniac]

Here's a solution to avoid the need of having the replaced string to be longer:

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START_STRING="Test string..."
END_STRING="Want tea?"
WAIT_TIME=2
echo -en "$START_STRING\r"; sleep $WAIT_TIME; echo -en "$END_STRING"; for i in $(seq 1 $(echo -en "$START_STRING" | wc -m)); do echo -en " "; done; echo -en "\n"

It needs to be more polished, but atleast it works for me

[naw]

echo is not supported on all shells (often aliased to print command) but should be the same on all bash shells.
I suggest you use printf command instead. printf is very useful (more powerful) and is implemented the same way - well worth reading up on.
Would be very nice if PB supported the powerful printformatting conventions that printf uses:

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while true
do
printf "${ctr}\r"
let ctr=${ctr}+1
done

or replace

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printf "${ctr}/r"

with

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printf "%5d\r" ${ctr}

or

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printf "%05d\r" ${ctr}