while_ejemplos.sh

#!/bin/bash

var=0
userid=1

while [ $userid -ne $var ];do

	read -p "ingrese usuario: " user

	userid=$(grep ^$user /etc/passwd | cut -d ":" -f 3)

done




# recorrer ficheros

file=/etc/passwd

while read -r linea; do

	echo $linea | grep ^ftp > /dev/null && break

done < $file

echo $linea


echo fin del programa