Programas ya echos

Aca les voi a presentar toda una coleccion de codigo echo por mi para que al igual que yo aprendo del codigo de los demas i de la teoria que los demas exponen les dego una lista de todos los programas que voi haciendo.
Script para hacer bucles
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W=0
A=0
c=0
for a in `seq 1 $1`; do
c=`( echo $c + 1 | bc )`
echo respuesta numero $c : $W
for e in `seq 1 $2`; do
W=`( echo $W+1 | bc )`
if [ "$4" == "0" ]
then
$3 $W
else
$3
fi
done
done
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
* * This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
* * You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
* MA 02110-1301, USA.
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Sintaxis: Bucles num num2 "comando a ejecutar" num*num2 es el resultado de las vueltas dadas.

Programa para cambiar el fondo del escritorio

cat "archivo a poner" > "imguen configuarada como fondo de escritorio"