Flush your bash command history

Lose your terminal session? Did your VPN drop? Did you have a bunch of work you were doing in your bash session and because you lost connection, your session closed uncleanly and you wanted to retrieve your command history?

Yeah. Sucks, huh?

Here's a simple fix:

insert the following in your ~/.bashrc :

# vi ~/.bashrc

export PROMPT_COMMAND='history -a'

and resource:

# .~/.bashrc

There.

Now your commands will "flush" to the history file immediately.



You're welcome.

-Wrex

Recover a file with LSOF....

Just a quick and dirty of how to recover a file in LSOF.

lsof (List Open Files) is a *nix tool that will show open files and network connections. Of course, it's also available for OS X.

You can recover deleted files with it.

If you have ever deleted a file by mistake you can recover the deleted file. 

For example, to recover a missing messages log used by Syslog you can search for it via this command:

bash:~  lsof | grep messages

You should see something similar to:

syslogd   15328      root    2w      REG              253,2   1419873               983175 /var/log/messages.5 (deleted)

You want to find what is marked as deleted in parenthesis.  The process (15328) still has the file open. Without this process keeping the file open we would have lost the file permanently. This is important. Once the process stops, you won't be able to trace the file this way, so avoid rebooting or stopping the process entirely, until after you've recovered the lost file.

We can view the missing info by looking inside the proc filesystem, the process id (15328), and in the file descriptor (fd). The fd is found in the 4th entry, above (2w in this example):

bash:~  cat /proc/15328/fd/2

This outputs the contents the deleted messages.5 file. As you can see, the data is still there. Now, just redirect the contents back to /var/log/messages.5:

bash:~  cat /proc/15328/fd/2 > /var/log/messages.5

That's all there is to it. You have recovered the file with all the data back to its original location. You should also restart the process, writing to the file(s) recovered.

This is just one of many examples of how lsof can be very useful. Be sure to check out the Man pages and other docs.

So you want a fresh Ubu install and don't want to hunt-down all you currently packages....

..and reinstall them all one-by-one or write a silly script to handle them all. Well, here's a simple solution: 

Save currently installed packages:
 # dpkg --get-selections > packages.installed 

Save this off and then copy to new machine or back to re-installed, then do:

 # dpkg --set-selections < packages.installed
(* Note: You may want to prune the list of software that you don't want to install or is incompatible if newer version of OS, before doing import above.)

 Then do: # dselect

Also, don't forget to save and copy over your /etc/apt/sources.list of course.

 That's it! Simple, eh?

Using Sprint EVDO card (S620) in Linux

Some quick/dirty notes in getting your Sprint S620 EVDO card working in Linux (I am currently using Fedora FC8):

Note Sprint S620 card vendor ID is 1410 and product is 1110. You can ascertain this by the following (as root):
[root@localhost ~]# cat /proc/bus/usb/devices
T: Bus=02 Lev=01 Prnt=01 Port=00 Cnt=01 Dev#= 2 Spd=12 MxCh= 0
D: Ver= 1.10 Cls=00(>ifc ) Sub=00 Prot=00 MxPS=64 #Cfgs= 1
P: Vendor=1410 ProdID=1110 Rev= 0.00
S: Manufacturer=Novatel Wireless Inc.
S: Product=Novatel Wireless Merlin CDMA
C:* #Ifs= 2 Cfg#= 1 Atr=a0 MxPwr=100mA
I: If#= 0 Alt= 0 #EPs= 3 Cls=ff(vend.) Sub=ff Prot=ff Driver=usbserial_generic
E: Ad=81(I) Atr=03(Int.) MxPS= 64 Ivl=128ms
E: Ad=82(I) Atr=02(Bulk) MxPS= 64 Ivl=0ms
E: Ad=02(O) Atr=02(Bulk) MxPS= 64 Ivl=0ms
I: If#= 1 Alt= 0 #EPs= 2 Cls=ff(vend.) Sub=ff Prot=ff Driver=usbserial_generic
E: Ad=84(I) Atr=02(Bulk) MxPS= 64 Ivl=0ms
E: Ad=04(O) Atr=02(Bulk) MxPS= 64 Ivl=0ms


As root:

Check to see if module loaded:
[root@localhost ~]# modprobe uhci-hcd
[root@localhost ~]# modprobe ohci-hcd
[root@localhost ~]# modprobe usbserial vendor=0x1410 product=0x1110

Unload Module (Some reason, it wouldn't work, until I removed it, first):
[root@localhost ~]# modprobe -r usbserial
[root@localhost ~]# modprobe -r ehci-hcd
[root@localhost ~]# modprobe -r ohci-hcd

Re-load OHCI and probe for card again:
[root@localhost ~]# modprobe ohci-hcd
[root@localhost ~]# modprobe usbserial vendor=0x1410 product=0x1110

mknod the device you are going to dial through:
[root@localhost ~]# mknod /dev/ttyUSB0 c 188 0

Now set up your favorite PPP dialer (I use kppp, myself) and have phun.

UNIX: Simple one-liner to chop last field from file

So, I wanted to chop off the last field in a file extension (bob.joy.txt, for example).
Here's is a simple solution, using reverse (rev), ls, cut and a for loop:

for i in `ls *.txt`; do mv $i `echo $i|rev |cut -d '.' -f2-|rev`;done

There's prob a cleaner way, but this was quick and easy.

Veritas Cluster GUI 4.x in OSX howto

I hacked this together, so I can run the VCS cluster GUI on my Mac, instead of relying on Winbloze. I am almost ready to dump MicroCrap altogether! :-)

I'll be working on the VEA gui, later.

While I prefer command-line, sometimes a GUI is still nice. Especially, in a complex cluster arrangement, such as the one I admin.





Veritas Cluster Manager 4.x in Mac OS X

Configuring the Veritas Cluster Manager to use the Mac OS X using OS X native Java.

1- Copy the Veritas GUI from server (/opt/VRTSvcs/gui) to a location of choice on your Mac.
2- Edit hagui script (this script, below) to reflect the location of VRTSvcs and the path to your JAVA Home
3- Open a terminal and run /path/to/VRTSvcs/hagui

The following is a copy of the modified hagui script (modify to your liking):
**************************************************************
#!/bin/sh
#
# START COPYRIGHT-NOTICE: 1998, 2003
#
# Copyright 1998, 2003 VERITAS Software Corporation.
# All rights reserved.
#
# VERITAS, VERITAS SOFTWARE, the VERITAS logo and all other VERITAS
# product names and slogans are trademarks or registered trademarks
# of VERITAS Software Corporation in the USA and/or other countries.
# Other product names and/or slogans mentioned herein may be trade-
# marks or registered trademarks of their respective companies.
#
# END COPYRIGHT-NOTICE.
#

# change the environment's classpath and
# java_home
#unset JAVA_HOME
#unset CLASSPATH
PATH=".:$PATH"
export PATH

#VCS_HOME="/opt/VRTSvcs"
VCS_HOME="/Users/wallen/VRTSvcs"

#JAVA_HOME=$VCS_HOME/gui/jre
LIB_PATH=$VCS_HOME/gui/lib
LANG_PATH=$VCS_HOME/gui/lang

LD_LIBRARY_PATH=$LIB_PATH
export LD_LIBRARY_PATH

BCLASSPATH=${LANG_PATH}:${LIB_PATH}/VCSGui.jar:${LIB_PATH}/gui_images.jar:${LIB_PATH}/sounds.jar:${LIB_PATH}/VxHelpViewer.jar:${LIB_PATH}/VxHelpViewerl10n.jar

DEBUG=0
if [ "$1" = "-D" ] ; then
DEBUG=1
shift 1
fi

if [ "$#" = 0 ] ; then
if [ "$CSGA_DIR" = "" ] ; then
CONF_PATH=$VCS_HOME/gui/
else
CONF_PATH=$CSGA_DIR
fi
elif [ "$#" = 1 ] ; then
CONF_PATH=$*
shift 1
elif [ "$#" -gt 1 ] ; then
if [ -d "$1" ] ; then
CONF_PATH=$1
shift 1
elif [ "$1" != "-h" ] && [ "$1" != "-p" ] ; then
echo "$1: configuration directory doesn't exist."
exit 1
fi
else
echo "$SELFNAME: configuration directory is incorrect!"
exit 1
fi


CLASSPATH=${CONF_PATH}:$BCLASSPATH:$JAVA_HOME/lib/rt.jar:$JAVA_HOME/lib/i18n.jar
export CLASSPATH

if [ $DEBUG = 0 ] ; then
exec $JAVA_HOME/bin/java -Dbase.dir="/opt/VRTSvcs/gui" -classpath $CLASSPATH -mx128m VCSGui $* > /dev/null
else
exec $JAVA_HOME/bin/java -Dbase.dir="/opt/VRTSvcs/gui" -classpath $CLASSPATH -mx128m VCSGui $*
fi