Bash

Perforce P4D init.d script (CentOS)

Tyler Bishop 0 Comments

Basic init script to control p4 / p4d for perforce.

Uses /var/p4 as the working directory and p4service as the user.

#!/bin/sh
#
#
# Startup/shutdown script for Perforce
#

# Source function library. this is where ‘daemon’ comes from
. /etc/init.d/functions

prog=Perforce Server

p4d_bin=/usr/local/bin/p4d
p4_bin=/usr/local/bin/p4
p4user=p4service
p4authserver=p4authserver:1667
p4root=/var/p4/root
p4journal=/var/p4/journal
p4port=1818
p4log=/var/p4/log
p4loglevel=3

start () {
echo -n $”Starting $prog: ”

# start

#If you wish to use a perforce auth server add this into the below command line.
# -a $p4authserver

 

#Start the daemon as the p4user.

/bin/su $p4user -c “$p4d_bin -r $p4root -J $p4journal -p $p4port -L $p4log -v server=$p4loglevel -d” &>/dev/null
}

stop () {
# stop
echo -n $”Stopping $prog: ”
$p4_bin -p $p4port admin stop
}

restart() {
stop
start
}

case $1 in
start)
start
;;
stop)
stop
;;
restart)
restart
;;
*)

echo $”Usage: $prog {start|stop|restart}”
exit 3
esac

exit $RETVAL

Another basic shell script

Alex Underwood 0 Comments

The great thing about shell scripts is that they are a great way to solve complex problems that can cost you a lot of time to do manually. To this end, I had a client that needed some videos (that was made by using the Video production services Toronto) encoded on his server that didn’t encode properly. For an experienced script writer this would take about 5 minutes to write. It also makes it so that if the client wants to use it they can. The configuration was nice because the input and output file name was the same, just the extension was different. This is not very polished, if it were I would

A)run it as the same user

B)Put it in the user’s homedir

C)Make it so that it was password protected and executable via PHP script so the user wouldn’t require any bash experience at all but could upload a list via FTP and just run it.

#!/bin/bash

for video in `cat /root/list.txt` #We will run a loop where each line in list.txt is run as a variable $video.
do
mv /home/user/public_html/media/videos/flv/$video.flv /home/user/public_html/media/videos/flv/$video.flv.old #back up old files
ffmpeg -y -b 1500 -r 25 -i  /home/gogreenc/public_html/media/videos/vid/$video.* -f flv -s 640×480 -deinterlace -ac 1 -ar 41400 /home/user/public_html/media/videos/flv/$video.flv #encode new file, 640X480 out, FLV format deinterlaced.
chown user:user /home/user/public_html/media/videos/flv/$video.flv #chown to the right user. Not required if running as the right user.
done

A quickie MySQL backup script

Alex Underwood 0 Comments

I’ve seen my fair share of clients that need basic MySQL backups but have no control panel or don’t want to bother with Control panel based backups. This is a really simple setup that lets you do DB backups and put them in a local directory of the server. It would likely be easily modified to rsync to another server as well if you wanted to. There are a ton of options that could be added to this, your imagination (and shell scripting capacity) are the only limitations. Some suggestions I have would be

-Mail on success or failure and on old file deletion

-Connect to a remote DB

-Monitor the overall size

Well enough with the abstract, on to the shell!

#!/bin/bash
date=`date +%Y%m%d`
mysqldump –all-databases > /mysqlbackups/mysql-$date.sql
find /mysqlbackups/ -atime +30 -delete

If you notice, this takes up all of 4 lines. The first one is the she-bang, the second is establishing the date time stamp, the third dumps the databases and the last one purges any old backups. The only real variable you have to change here is the “+30” so that it is the number of days you want to retain the backups for minus one.

Adding lots of IPs to a debian box

Alex Underwood 0 Comments

At work I had a client with a Debian system that needed a bunch of IPs added to it. Since it doesn’t really support ranges (at least that I can find) I came up with the following script.

#/bin/bash
j=42
for i in  {186..190}
do
j=$(expr $j + 1)
echo auto eth0:$j >> interfaces; echo iface eth0:$j inet static >> interfaces; echo address 192.168.41.$i >> interfaces; echo netmask 255.255.255.248 >> interfaces;
done

How it works is that j is the last IP in the ranges currently set in the interfaces file. The address is defined in the script, and the range is defined in the i= section. Just change the numbers to match what you want, put this into /etc/networking, run it and restart networking. This is only for five IPs but you could do hundreds or thousands this way if it was the desired affect. Or you can use a distro that supports ranges :>

Cool One Liners #1

Alex Underwood 1 Comment

Welcome to the first edition of Cool One Liners. This will be a collection of one line commands you can use via BASH or another shell/scripting language to do something useful. Creativity will definitely be a big merit. Todays one liner is:

cat /var/log/secure | grep Failed | grep sshd | grep root | awk ‘{print $11}’ | sort | uniq -c | sort -n

What does it do? This takes the secure log, sorts out failed login attempts and then makes it so that the IPs are sorted based on the number attempts. Handy to try and track down brute force attempts on an box running SSH. As an example, I generated a few failed logins.

[root@DNS01 log]: cat /var/log/secure | grep Fail

May  9 03:31:58 DNS01 sshd[10706]: Failed password for root from 127.0.0.1 port 34900 ssh2
May  9 03:32:00 DNS01 sshd[10706]: Failed password for root from 127.0.0.1 port 34900 ssh2
May  9 03:32:04 DNS01 sshd[10706]: Failed password for root from 127.0.0.1 port 34900 ssh2

After this I ran the command given. Notice how the IPs have the number to the left of them. If this were a list the number with the most logins is going to be at the bottom.

[root@DNS01 log]: cat /var/log/secure | grep Failed | grep sshd | grep root | awk '{print $11}' | sort | uniq -c | sort -n

3 127.0.0.1

This command also serves an additional interesting use. Lets say someone is probing your machine, and they happen to be attempting to brute force some nonstandard account names in the hope of coming up with something on the system that is there and has a weak password. This script will also list any invalid users that attempt to log in as well. An example would be if I attempted to log in with the user root1. The output would look like:

[root@DNS01 log]: cat /var/log/secure | grep Failed | grep sshd | grep root | awk '{print $11}' | sort | uniq -c | sort -n

3 127.0.0.1
3 root1

In another blog we will likely take this command, convert it into a shell script, and make it so it will run as a cron job and email us periodic digests.

Pipin ain’t easy (unless you read this guide)

Alex Underwood 1 Comment

I have gone over more than a few Linux based commands at this point, so I want to introduce a new way of using them; Pipes. Pipes are really cool because they will let you take the command and put its output into another command. There are a nearly infinite amount of ways to use them as well. Enough with the introductions, lets get on to the commands. Lets say that I want to determine the number of connections currently open at the moment on port 80. We can do the command

netstat -anp

And it will give us a distinct number of entries. We are left looking for traffic that is on port 80, and we have a bunch of lines we don’t care to bother with quite frankly. This is where the pipe comes in.

netstat -anp | grep :80

This will show any traffic that is to port 80, or any traffic that is going to port 80 on a remote server. Lets say we have a huge amount of traffic though, and want to just get a count. If you have a high use server counting by hand is a nuisance at best and virtually impossible at worse. At this point we would just throw the results of our grep into another pipe like this:

netstat -anp | grep :80 | wc -l

And then we have a raw number of accounts used on port 80. Pretty neat. Because pipes are an infinitely versatile tool we can use them for dealing with static files or dealing with the server in real time using utilities like tail. Want to know more about tail? Check out my next blog, I’m going to show some of the tricks on server side troubleshooting.

Sort Files with Bash

Tyler Bishop 0 Comments

I’ve always been a fan of collecting fonts, as I go across the net I find random font files and save them for later use. Seems like I can never find the fonts I want because they are scattered all over and unsorted. Got tired of having unorganized font files laying around, so I wrote this to organize them.

#!/bin/bash
#Edit path to the location of where you want your fonts organized
#create a folder called "Unsorted" and place all the files into that.
path="Fonts/"
cd "${path}Unsorted/"
for mFile in *
do
  #Check rather its a file or folder, if its a folder skip it!
  if ! [[ -f $mFile ]]; then continue; fi

  #Grab the first letter of the filename and set it to $mFirstChar/
  mFirstChar="${mFile:0:1}"

  #Convert all lowercase fist letters to upper case.
  mFL=$(tr "[:lower:]" "[:upper:]"<<<"$mFirstChar")

  #If the filename contains any chars such as "!@#$%^&*()" at the beginning
  # set the $mFl var to "MSC".
  if [[ $mFL != [[:alpha:]] ]]; then mFL="MSC"; fi

  #Make directories, prompt for overwrite and create dir if it does not exists.
  mkdir -ip "../${mFL}"

  #Move files to there new home.
  mv -v "${mFile}" "../${mFL}/${mFile}"
done