如何在Linux中做一个计数器？

Question

I'm trying to write a script where I want to make a countdown of three seconds (probably with the sleep command), but every second I want to display the text "break".

After every second, I want to display a countdown next to the word "break", but the line of text should stay in place. The word "break" must stay in one place; only the number should change.

Answer 1

You can use ANSI terminal control sequences . Like this:

# Save the cursor position
echo -en "\033[s";

for i in {3..1} ; do

    echo -n "break $i"
    sleep 1

    # Restore the cursor position
    echo -en "\033[u";

done

# Print newline at the end
echo

If you want the last break 1 to disappear from screen then change the last line to

# Clear the line at the end
echo -en "\033[K"

Answer 2

In bash, you can use a for loop, and the character \\r to move the cursor back the the beginning of the line:

for ((i=3; i; --i)) ; do
    printf 'break %d\r' $i
    sleep 1
done