Hostname

Source

how to change the hostname of your machine

Not-so intrusive script
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#!/bin/bash
#
usage() {
   echo "usage : $0 <new hostname>"
   exit 1
}

[ "$1" ] || usage

old=$(hostname)
new=$1

for file in \
   /etc/exim4/update-exim4.conf.conf \
   /etc/printcap \
   /etc/hostname \
   /etc/hosts \
   /etc/ssh/ssh_host_rsa_key.pub \
   /etc/ssh/ssh_host_dsa_key.pub \
   /etc/motd \
   /etc/ssmtp/ssmtp.conf
do
   [ -f $file ] && sed -i.old -e "s:$old:$new:g" $file
done
Not-so intrusive script
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#!/bin/bash
#

# Fetching new and old hostname
OLD_HOSTNAME=$(hostname)
NEW_HOSTNAME=$1

WHIPTAIL_TITLE="Changing hostname"
WHIPTAIL_BACKTITLE="ShrimpDev <dev@csoellinger.at>"
WHIPTAIL_TEXT="Below you will find a checklist with all files where we found your old hostname \"${OLD_HOSTNAME}\" inside /etc\n\nPlease check which files we should update to your new hostname \"${NEW_HOSTNAME}\""

not_root() {
    echo "ERROR: You have to be root to execute this script"
    exit 1
}

usage() {
    echo "usage : $0 <new hostname> [Optional:--backup/Set backup mode on] [Optional:--debug/Set debug mode on]"
    exit 1
}

# Check if user is root
[ $EUID != 0 ] && not_root

# Check if we have at least one parameter
[ "$1" ] || usage

[ "$1" == "--backup" ] && usage
[ "$1" == "--debug" ] && usage

DEBUG="NO"
BACKUP="NO"

if [ "$2" == "--debug" ] || [ "$3" == "--debug" ]; then
    DEBUG="YES"
fi

if [ "$2" == "--backup" ] || [ "$3" == "--backup" ]; then
    BACKUP="YES"
fi

[ "$DEBUG" == "YES" ] && echo "DEBUG (NO FILES WILL BE CHANGED)"
[ "$BACKUP" == "YES" ] && echo "BACKUP MODE ON"

# Grep all possible targets
TARGETS=($(grep "$OLD_HOSTNAME" /etc/ -rl))
let TARGETSLENGTH=${#TARGETS[@]}

CHECKLIST=()
for ((i=0; i<${#TARGETS[@]}; i++)); do
    CHECKLIST+=("${TARGETS[$i]}" "" "ON")
done

CHECKLIST_RESULT=$(whiptail --clear --fb --title "$WHIPTAIL_TITLE" --backtitle "$WHIPTAIL_BACKTITLE" --checklist "$WHIPTAIL_TEXT" 30 80 $TARGETSLENGTH "${CHECKLIST[@]}" 3>&2 2>&1 1>&3)
CHECKLIST_RESULT=${CHECKLIST_RESULT//\"/}
CHECKLIST_RESULT_ARR=(`echo $CHECKLIST_RESULT | tr ' ' '\n'`)

clear

for CHECKLIST_ITEM in "${CHECKLIST_RESULT_ARR[@]}"; do
    echo "sed \"s:${OLD_HOSTNAME}:${NEW_HOSTNAME}:g\" \"${CHECKLIST_ITEM}\" > \"${CHECKLIST_ITEM}.tmp\""
    [ "$DEBUG" == "NO" ] && sed "s:$OLD_HOSTNAME:$NEW_HOSTNAME:g" "$CHECKLIST_ITEM" > "$CHECKLIST_ITEM.tmp"

    if [ "$BACKUP" == "YES" ]; then
        echo "cp \"${CHECKLIST_ITEM}\" \"${CHECKLIST_ITEM}.BCK\""
        [ "$DEBUG" == "NO" ] && cp "$CHECKLIST_ITEM" "$CHECKLIST_ITEM.BCK"
    fi

    echo "mv -f \"${CHECKLIST_ITEM}.tmp\" \"${CHECKLIST_ITEM}\""
    [ "$DEBUG" == "NO" ] && mv -f "$CHECKLIST_ITEM.tmp" "$CHECKLIST_ITEM"

    echo ""
done

exit 0
Last update: Jun 03, 2025