Bash script to set up an ad hoc wireless network

Question

This script creates an adhoc network using hostapd. I have tested it and seems to work reliably. I am new to linux networking and not sure if this is a recommended way to create an adhoc network this way.

#!/bin/bash
#set -x
DEVICE=wlan0
CONFIG_FILE=./hostapd.conf
ConfigureDevice()
{
    if ! sudo iwconfig 2>/dev/null | grep $DEVICE >/dev/null;then
        echo $DEVICE not found!
        exit -1
    fi

    #Ensure config file exists
    if [ ! -e $CONFIG_FILE ]
    then
        echo "Can't find hostapd config file"
        exit -1
    fi

    sudo service isc-dhcp-server stop
    sudo pkill hostapd
    sudo ifdown  $DEVICE 
    sudo ifconfig $DEVICE up 192.168.1.100 netmask 255.255.255.0
    sudo service isc-dhcp-server start
    sudo hostapd -B $CONFIG_FILE

}
cd ${0%/*}  #make current working directory the directory of the bash script
ConfigureDevice

Answer 1

Not answering your actual question, but offering a couple of code comments:

use cd -- "$(dirname -- "$0")"

• if the script is in the PATH and someone just enters the script name, you will try to cd to the (probably non-existant) "script name" directory in the current dir.

use grep -q $DEVICE

• that is a bit speedier since, if it finds a match, it exits immediately instead of having to read the entire input looking for all matches.