Ceva scripturi Bash utile ...

Scripturi care permit schimbarea rapida a MAC+IP

getmac - Primeste ca parametru un IP si returneaza MAC-ul acestuia sau "" daca nu exista in retea nodul cu pricina.

/usr/local/bin/getmac

#!/bin/sh
 
if [[ ! $IFDEVICE ]]; then
        IFDEVICE="eth0";
fi
 
mac=`arping -I $IFDEVICE $1 -c 3 | grep reply | cut -f2 -d\[ | cut -f1 -d\] | uniq`
echo $mac

be - Primeste ca parametru un IP si schimba MAC-ul si IP-ul pentru un device.

/usr/local/bin/be

#!/bin/bash
 
if [[ ! $IFDEVICE ]]; then
        IFDEVICE="eth0"
fi
 
gip=`echo -e "$1\t"`
echo -e " IP is $1."
mac=`cat /etc/stored | grep "$gip" | cut -f2`
echo -e "MAC is $mac."
if [[ $mac != "" ]]; then
        ifconfig $IFDEVICE down
        ifconfig $IFDEVICE hw ether $mac
        ifconfig $IFDEVICE $1 netmask 255.255.248.0 broadcast 10.10.17.255
        route add default gw 10.10.17.1
        # echo "nameserver 10.10.17.1" > /etc/resolv.conf
else
        echo "$1 has not an associated MAC."
fi

switchuser - Schimba MAC-ul si IP-ul aleator conform unuia stocat in /etc/stored folosind scripturile anterioare.

/usr/local/bin/switchuser

#!/bin/bash
 
notfound=1
while [[ $notfound -eq 1 ]]; do
        rip=`echo "$RANDOM % 252 + 3" | bc`
        for i in `seq $rip 254`; do
                randip="10.10.17.$i"
                gip=`echo -e "$randip\t"`
                if [[ `cat /etc/stored | grep "$gip" | cut -f2` != "" ]]; then
                        if [[ `getmac $randip` == "" ]]; then
                                be $randip
                                exit 0
                                notfound=1
                        else
                                echo "IP $randip is already active."
                        fi
                else
                        echo "$randip has no MAC associated."
                fi
        done
done

Scripturile folosesc fisierul de configurare /etc/stored in care se adauga perechi de forma: IP\tMAC, e.g.

10.10.17.241    00:20:ED:95:2A:A1
10.10.17.242    4C:00:10:53:BF:A5

precum si variabila din enviroment IFDEVICE daca este definita. e.g. daca vrem sa schimbam ip-ul doar pentru device-ul eth1 atunci apelam la:

# IFDEVICE=eth1 switchuser

Script care lanseaza in fundal o anumita comanda data ca parametru de intrare

Puteti lasa o comanda sa se execute in fundal fara ca ea sa fie intrerupta la iesirea dumneavoastra din sistem folosind urmatorul script pe care l-am numit silent. (output-ul nu este salvat, pentru aceasta puteti folosi nohup)

#!/bin/bash
 
echo "Executing \"$*\""
setsid bash -c $* 2>>/dev/null 1>>/dev/null < /dev/null &

Scriptul il puteti folosi de exemplu:

$ silent wget -c -t 0 www.bigfiles.com/ubuntu.iso

Script ce elimina zona asociata unui domeniu dat ca parametru de intrare

Puteti elimina portiunea din named.conf de la zone "nume.domeniu.dat.ca.parametru.de.intrare" { pâna la acolada inchisa asociata acoladei deschise de mai sus.

Scriptul este:

#!/bin/bash
 
# Bind zone remove script
#
# Copyright (C) 2005 Silvian Cretu 
#
# 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., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA. 
 
if [ ! $# = 1 ]; then
    echo "Usage: $0 domain";
    echo "The path to named.conf is defined inside the script";
    		 else
	pathToNamedDotConf=/etc/named.conf
 
	x=$(grep -n "zone \"$1\" {" $pathToNamedDotConf | cut -f1 -d:)
	sed $x,/\}\;/d $pathToNamedDotConf > temp
	c=$(sed -n $x'p' < temp)
	if [ "x`echo $c | grep "zone"`" = "x" ]
	then
		sed $x' d' temp > $pathToNamedDotConf
	else
		cat temp > $pathToNamedDotConf
	fi
	rm -f temp
	exit
fi

Cautarea unui fisier ce contine un anumit string

find /path -name "*" -exec grep -H ""  '{}' \;

sau

grep -Hr "" /path/

Fireste, poate fi atat un sir de caractere cat si orice fel de expresie regulata suportata de versiunea particulara de grep disponibila pe masina in cauza.
Deasemenea, pentru a cauta fara a face diferenta intre majuscule si minuscule, adaugati parametrul -i la grep.

Daca doriti ca in output-ul comenzii grep expresia cautata sa fie cautata sa fie evidentiata puteti folosi parametrul --color astfel:

grep --color -Hr "" /path/

Stergerea fisierelor backup

Asa cum stiti, prin traditie in *NIX, editoarele text fac o copie de siguranta fisierelor editate, copie de siguranta ce este denumita identic cu fisierul initial plus caracterul tilda (~). Ei bine... in cazul aplicatiilor web, acest backup mai mult dauneaza decat sa ajute. Nu ar fi prea placut sa aveti un index.php~ in DocumentRoot

find /path -name "*~" | xargs -n 20 rm -f

Probleme cu spatiul pe disc?

Nu stiti unde "vi s-a dus" spatiul de pe disc si e cam greu sa verificati fiecare director in parte?
Linia urmatoare va ajuta, facand totodata si o sortare.

du --max-depth=1 /path | sort -rn

Gasirea fisierelor duplicate intr-un director

Aveti prea multe mp3-uri si majoritatea sunt duplicate dar cu alt nume sau orice de genul folositi scriptul de mai jos:D Eventual adaugati si un -maxdepth 1 sa nu fie recursiv.

#!/bin/sh
if [ ! -d "$1" ]; then 
  echo "Usage $0 

Calcularea recordului de uptime

Scriptul urmator va trebui plasat in crontab astfel incat sa ruleze periodic, de exemplu, din ora in ora. El va afisa in fisierul $output (initial /var/log/uptimeRecord.log) output-ul comenzilor uptime si date (adica uptime-ul record si data la care a fost inregistrat).

#!/bin/bash
 
# Copyright (C) 2006 Silvian Cretu 
#
# 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., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA. 
 
output='/var/log/uptimeRecord.log'
 
function compareHrs
{
        uptimeCurent=`uptime`
        if [ `echo $uptimeCurent | grep -c day` == '0' ]; then
#               echo Uptime mai mic de o zi
                uptimeCurentOre=`uptime | awk '{print $3}'`
                uptimeRecordOre=`cat $output | head -1 | awk '{print $3}'`
        else
                uptimeCurentOre=`uptime | awk '{print $5}'`
                uptimeRecordOre=`cat $output | head -1 | awk '{print $5}'`
        fi
        if [ `expr length $uptimeCurentOre` \> `expr length $uptimeRecordOre` ]; then
#               echo Nou record - Uptime curent mai mare cu cateva ore decat uptime-ul record 1
                uptime > $output
                date >> $output
        else
                if [ `expr length $uptimeCurentOre` == `expr length $uptimeRecordOre` ]; then
                        uptimeCurentOra=`echo $uptimeCurentOre | cut -d":" -f1`
                        uptimeRecordOra=`echo $uptimeRecordOre | cut -d":" -f1`
                        if [ $uptimeCurentOra -gt $uptimeRecordOra ]; then
#                               echo Nou record - Uptime curent mai mare cu cateva ore decat uptime-ul record 2
                                uptime > $output
                                date >> $output
                        fi
                fi
        fi
}
 
if [ -a $output ]; then
        uptimeCurent=`uptime`
        uptimeRecord=`cat $output | head -1`
        if [ `echo $uptimeCurent | grep -c day` == '0' ]; then
#               echo Uptime mai mic de o zi
                if [ `echo $uptimeRecord | grep -c day` == '0' ]; then
#                       echo Uptime record mai mic de o zi, comparam orele
                        compareHrs
#               else
#                       echo Uptime record mai mare ca uptime curent
                fi
        else
#               echo Uptime mai mare de o zi
                if [ `echo $uptimeRecord | grep -c day` == '0' ]; then
#                       echo Uptime record mai mic de o zi
                        uptime > $output
                        date >> $output
                else
                        uptimeCurentZile=`uptime | awk '{print $3}'`
                        uptimeRecordZile=`cat $output | head -1 | awk '{print $3}'`
                        if [ $uptimeCurentZile -eq $uptimeRecordZile ]; then
#                               echo Uptime in zile egal
                                compareHrs
                        else
                                if [ $uptimeCurentZile -gt $uptimeRecordZile ]; then
#                                       echo Record nou
                                        uptime > $output
                                        date >> $output
                                fi
                        fi
                fi
        fi
else
#       echo Fisierul nu exista, deci trebuie creat. Recordul e uptime-ul curent
        uptime > $output
        date >> $output
fi
 
exit 0

Stergere directoare vechi de pe o partitie pentru salvarea spatiului

Scriptul urmator poate fi plasat in cron si rulat cam din ora in ora pentru a sterge directoare vechi. Un exemplu clasic este stergerea jpeg-urilor generate de camera de supraveghere conectata la un server Linux:

#!/bin/bash
 
# Copyright (C) 2005-2007 Silvian Cretu 
#
# 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., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA. 
 
# Constante:
partitie=/var/www # partitia monitorizata
procentMaxim="97%" # procentul maxim de ocupare acceptat pt partitia monitorizata
X=1 # se vor sterge directoarele mai vechi de X zile
director=/var/www/html/camera/events/2 # directorul din care se vor sterge subdirectoarele
 
# Cat de ocupata este partitia monitorizata (in procente):
procentOcupare=$(df -h | grep $partitie | awk '{print $5}')
 
if [[ "$procentMaxim" < "$procentOcupare" ]] || [ "$procentOcupare" == "100%" ];
	then # trebuie sterse directoarele mai vechi de X zile
		find $director -type d -mtime +$X -exec rm -rf {} \;
fi
 
exit