Nicholas Dille

Automation, DevOps and Containerization

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Embedding Control Characters

Published on 30 Nov 2007
Tags #SSH #Bash

The following example demonstrates how to use control characters to change characters on the current line:

echo -n aaa
sleep 2
echo -n $'b'b
sleep 2
echo -n $'r'c

Keeping a console alive:

#!/bin/bash

function wakeup() {
    echo -n $'r';
    exit 0;
}

trap 'eval wakeup' INT

while true; do
    echo -n "k"; sleep 1;
    echo -n "e"; sleep 1;
    echo -n "e"; sleep 1;
    echo -n "p"; sleep 1;
    echo -n "i"; sleep 1;
    echo -n "n"; sleep 1;
    echo -n "g"; sleep 1;
    echo -n " a"; sleep 1;
    echo -n "l"; sleep 1;
    echo -n "i"; sleep 1;
    echo -n "v"; sleep 1;
    echo -n "e"; sleep 1;
    echo -n " ."; sleep 1;
    echo -n "."; sleep 1;
    echo -n ".";

    sleep 10;

    echo -n $'r'
    echo -n "                 "
    echo -n $'r'
done
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