Disk space - df command

df command:
Hit a quota the other day, disk was at 81% - issue was my inodes were all used up.. Can find like this:
Find inodes used - in either bare metal or openvz:

df -i

Solaris:

df -o i

ISO files - of drives and directories

Making a backup of files..
To make an ISO of a directory

mkisofs -o ./vps-20090517.iso backups/

To make ISO's from devices:

dd if=/dev/cdrom of=/var/tmp/disk.iso

Found this simply explained here - thanks!
here

Mondo - Achive Examples

Mondo archive examples - just got intro'd to this program at work about a year ago, works very well - creates ISO images of a running system that can be restored very simply later on by installing like an OS - from CD...

This basically what is in man mondoarchive - /home and other places are backed up in another fashion, so don't need to have these to restore my base desktop..

mondoarchive -Oi -7 -d /backups/mondo/ -E "/backups /home /media /opt /srv /vz" -N -p `hostname`-`date +%Y-%m-%d` -s 680m

• -O - backup (that's an uppercase "O")
• -i - backup to ISO files
• -d - backup destination
• -7 - compression level (0-9)
• -E - exclude list
• -N - Don't include network mounted filesystems
• -p - filename prefix - 'stead of mondorescue-1.iso, etc.
• -s - specify max ISO file sizes m or g

SSH Tips and Tricks

Notes for SSH - various access methods and use for ssh

Local Computer

Remote Computer

port 9999

Set up a local proxy that would forward all traffic (encrypted) through the remote server - in this example from an internet cafe, one would connect to remote server, set the browser to use a socks proxy of "localhost:9999" and now all internet traffic is encrypted to/from the remote server. ssh -D 9999 user@remote .. or if you run your SSH on the server on a different port, say 4000 - ssh -D 9999 -p 4000 user@remote Set your Socks proxy to localhost:9999 - all webtraffic encrypted through the tunnel to the remote server. Add more tunnels for FTP, POP3 and with some proxy config will be secure.

port 4000

port 1234

Tunneling: Local forwarding tunnel: set up a forwarding tunnel so when access localhost:1234 its forwarded to remote:23 ssh -L 1234:localhost:23 user@remote or if server uses port 4000 for ssh - ssh -L 1234:localhost:23 -p 4000 user@remote - here we are setting up secure telnet tunnel. Users access the remote server just by telnet to localhost:1234.

port 23 ssh runs on port 22 & 4000

port 23

Tunneling: Remote forwarding Tunnel: set up a remote tunnel so when access remote:1234 its forwarded to localhost:23 ssh -R 1234:localhost:23 user@remote - note the only difference is -L and -R. Here we are setting up secure telnet tunnel. Users on the remote server access the local server just by telnet to localhost:1234.

port 1234

X forwarding: Start X applications on remote server, send to localhost: ssh -X user@remote or for different ssh port: ssh -X -p 4000 user@remote The -X to forward X - if that is enabled on the remote server in /etc/sdh/sshd_config: X11Forward yes

port 22

Firefox forwarding, multiple instances: Start X applications on remote server, send to localhost: On localhost:xhost +; then login with the -X optoin to the server, then firefox -no-remote will force firefox to start on the server and that instance will be forwarded to localhost. To run another instance - since only one profile can run at once, create a profile with firefox -no-remote -ProfileManager&. From Ubuntu forums and Lifehacker

port 22

crontab

CRON FILES
/var/spool/cron/crontabs/username
/etc/cron.d/cron.deny, /etc/cron.d/cron.allow Set who to deny and allow

Numbering format is:
n Matches if field value is n
n, p, q matches of field value is n, p,q 10,40 (matches 10 & 40)
n-p Matches field has values between n&p inclusive
* always matches.

Use crontab -e to edit a file. Some systems by default set pico or nano
as the default editor - I prefer vi - to force that, add the following to your .bash_profile if you use bash.

export EDITOR=vi
export VISUAL=vi

Source it:

 % source ~/.bash_profile

Edit with crontab -e

Example
minute          0-59
hour            0-23
dayof month     1-31
month           1-12
dayofweek       0-6 0=sunday

0 0 1,15 * *  /some/path/to/a/command    # whatever on 1st, 15th of the month
10 3 * * 0 /usr/lib/newsyslog            # daily at 3:10am
15 17 * * 5 /usr/bin/banner "Time to go" > /dev/console    # send out the geeks at 5:15pm on Friday

View crontab file with crontab -l

finger

finger - good to see who is logged in, or idle (have not typed). Yes this can be used to see if someone is slacking off

user@example.com [~/notes]% finger
Login Name Tty Idle Login Time Office Office Phone
gregg ttyp0 1d Jan 5 20:04 (ppp-65-139-123-221.dsl.mabell.net)
gregg ttyp1 Jan 9 17:15 (ppp-65-139-123-221.dsl.mabell.net)
gregg ttyp2 15:08 Jan 9 23:44 (ppp-65-139-123-221.dsl.mabell.net)

grep & egrep

grep and egrep (extended grep) are fast useful utilities.

System V and GNU grep are different, but 90% the same. The one thing I notice lacking in SystemV is the -R flag that recursively digs down to find what I am looking for...

Find the word "style" in files in a directory

user@example:% grep style *

Find the work "style" recursively in a directory - won't work on Solaris.. yet..

user@example:% grep -R style *

List files except that contain "access"

user@example:% ls | grep -v access

List files except that contain "access -or- error"

user@example:% ls | egrep -v 'access|error'

List files except that contain start with "access" - use -e then a regex

user@example:% ls | egrep -e  '^access'

Grep a file for the word "access"

user@example:% grep access /var/log/http/error.log

ip, ifup, ifdown in CentOS/Redhat/Fedora

Redhat/Fedora /etc/sysconfig/network-scripts/ifcfg-ethN files and the ifup/ifdown scripts - these use the HWADDR variable and then set the name with the ip(8) command.

Rename eth1 to eth0:

# ip link set down eth1
# ip link set eth1 name eth0

Or if like me you simply cat the ifcfg-eth1 file to ifcfg-eth0 and its still
not working after a reboot - would not take an IP address via ifconfig, this fixed it:

# ip link set down eth1
# ip link set eth1 name eth1

Given the IP/NetmaskGateway are set in the files..

Much of this article is from here - thanks!

kill

kill -9 PID Kill the process mercilessly.
kill -15 PID Ask the process to nicely stop running
kill -HUP PID Refresh a running process after config file changes - I have used this one a lot after making changes to /etc/ssh/sshd_config
kill -HUP -1 (kill all of my processes)

===========================================

A nasty solution:

stick in the following line:

echo $$ > ~/PID

in the user's .login file. and issue the following
commands to logout (actually 'slaughter') the user:

kill -9 `cat ~/PID`

kind regards,
Jos aka jos@and.nl

ln

ln - link a files and directories

Create symbolic link "B" that points to real file "A" Be careful.

ln -s   a       b
        ^       ^
       must    destroyed
       exist   if exists

user@example.com [~/test]% ln -s ln.txt ln-notes.txt
user@example.com [~/test]% ln ln.txt ln-notes2.txt
user@example.com [~/test]% mkdir DIR 
user@example.com [~/test]% ln DIR symlinkdir    <-- Can make hard links for files, but not  directories
ln: `DIR': hard link not allowed for directory
user@example.com [~/test]% ln -s DIR symlinkdir
user@example.com [~/test]% ls -al
total 20
drwxr-xr-x  3 gregg gregg 4096 Jan 11 00:13 ./
drwx--x--x 27 gregg gregg 4096 Jan 11 00:12 ../
drwxr-xr-x  2 gregg gregg 4096 Jan 11 00:13 DIR/
lrwxrwxrwx  1 gregg gregg    6 Jan 11 00:13 ln-notes.txt -> ln.txt*
-rwxr-xr-x  1 gregg gregg  146 Jan 11 00:12 ln.txt*
lrwxrwxrwx  1 gregg gregg    3 Jan 11 00:13 symlinkdir -> DIR/

login and profiles

/etc/.login /etc/profiles

add commands to be executed at login to these, files, see login manpage for more information.

rsync

rsync - lots of uses - for pulling files off a server -and- not saturating the DSL line:

rsync -avz --port=4321 -e "ssh -p 4321" --bwlimit=120 --progress user@example.com:/home/cpmove-user.tar.gz .

-avz a - archive mode (preserve links/perms/modes) v - verbose, z - compression
--port=4321 -e "ssh -p 4321" Use a different ssh port if needed...
--bwlimit=120 Expressed in kBps - my 3Mb/s AT&T DSL line tops out at about 278kB/s - I set this to ~40% of that - the wife appreciates it :)
--progress See the progress as rsync is working..

swaks - smtp testing

A great writeup is here

Here is an example for my own purposes:

user@ ~ $ swaks --to user@mochabomb.com \
> --from=thing@mochabomb.spiffy 
> --auth \
> --auth-user=testuser@mochabomb.com \
> --auth-password=mypassword \
> --server mochabomb.com:587  

=== Trying mochabomb.com:587:25...
=== Connected to mochabomb.com:587.
<-  220-vps2.mochabomb.info ESMTP ChickenLips Byte #Transporter version 12.0.314.159.26.53.59-2 rev 17 build 5682.126-05a Tue, 01 Sep 2009 23:05:59 -0700 
<-  220-   No one is authorized to use this fine system to transport unsolicited, 
<-  220    and/or bulk e-mail and other cruft.
 -> EHLO mydesktopbox.gotdns.com
<-  250-vps2.mochabomb.info Hello adsl-##-###-##-147.dsl.pltn13.sbcglobal.net [##.##.##.147]
<-  250-SIZE 52428800
<-  250-PIPELINING
<-  250-AUTH PLAIN LOGIN
<-  250-STARTTLS
<-  250 HELP
 -> AUTH LOGIN
<-  334 VXNlcyahooWU6
 -> YWeWdogpileLm1vYexcite@homejb20=
<-  334 UGFzyeehawQ6
 -> TDgoogleyM=
<-  235 Authentication succeeded
 -> MAIL FROM:
<-  250 OK
 -> RCPT TO:
<-  250 Accepted
 -> DATA
<-  354 Enter message, ending with "." on a line by itself
 -> Date: Tue, 01 Sep 2009 23:05:57 -0700
 -> To: user@mochabomb.com
 -> From: thing@mochabomb.spiffy
 -> Subject: test Tue, 01 Sep 2009 23:05:57 -0700
 -> X-Mailer: swaks v20061116.0 jetmore.org/john/code/#swaks
 -> 
 -> This is a test mailing
 -> 
 -> .
<-  250 OK id=1Miiym-0001Mr-8O
 -> QUIT
<-  221 vps2.mochabomb.info closing connection
=== Connection closed with remote host.

Pretty simple package - Debian the package is "swaks".

tar archive

tar -cvf - `find . -print` > ../whatever.tar

truss

babysit processes
like snoop

truss -f -a -e -o /tmp/truss.out batchtest_4.2