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For those who hack a lot of Linux at the command line interface, backing up files such as config files before editing is a good habit to have. IMHO anyway. So to save time, a little script can be written, chmod +x, and placed into /usr/local/bin or some other that users have in their executable shell PATH. I name mine “bu” to make it easy, and it takes one command line argument which is the filename of the file you want to make a backup copy of. It is called by running something like $ bu myfile

Here’s the code. Comments welcome The code creates a timecode based on today’s date and the current time to the second, and appends that to the original filename. The a copy is saved with this new “timestamped” backup filename, right in the same directory. Easy-peasy! 

#!/bin/bash
OLDFILENAME=$1
DATECODE=$(date +%Y%m%d)
TIMECODE=$(date +%H%M%S)
NEWFILENAME="${OLDFILENAME}_backup${DATECODE}-$TIMECODE"
cp $OLDFILENAME $NEWFILENAME
SUCCESS=$?
if [ $SUCCESS -eq 0 ];then
 echo "OK! Copied \"$OLDFILENAME\" to \"$NEWFILENAME\""
else
 echo "FAIL! You'll need to try again!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!"
fi

Posted under Linux

Sometimes in testing network settings and authentication ( for instance when setting up a Samba server and users on a CentOS, Ubuntu, or Feroda Linux system) I often find it useful to force my Windows PC client to “forget” the login username and password that it has on record, for the current session, so that I may login again with another username/password combo. Easily accomplished, this Windows trick works on all modern Microsoft operating systems.

The situation: You need to login again to a network share on a Windows file server, or a Linux server,  without rebooting the client computer.

The fix: Disconnect from the shares using the NET command.

1. Open a command prompt. (My favorite way is: Win-R, type cmd, press Enter)
2. Type NET USE * /DELETE
3. It will prompt you for verification, type Y and Enter.

That’s it! Enjoy, and may your login be forgotten!

Courtesy, Microsoft: http://support.microsoft.com/kb/308582

Posted under Microsoft, Network, Software, Windows

The most awesome emulator of all time, puTTY.exe, just got even easier to use. Along with loggiong automatically into a SSH session add the Windows shortcut that loads a saved session and launches it, now you have one click shell access to your Linux host from your Windows PC.

Here’s how:

1. Download puTTY.exe
2. Save it to the folder  C:\puTTY\
3. Open a Windows Explorer window in C:\puTTY\
4. Run puTTY.exe once, and create a “saved session”, making note of what you name it. My example below uses the name my neatly named Saved Session
5. Right-click-drag puTTY.exe and drop it next to itself, this creates a shortcut to the .exe file.
6. Right-click the shortcut you just created, on the popup menu click Properties.
7. In the Target box, add -load “your-saved-session-name” after C:\putty\putty.exe
8. The final content in the target box should look like:

   C:\putty\putty.exe -load "my neatly named Saved Session"

9. Save the shortcut. Viola! Move or copy this shortcut anywhere you like (e.g. your Desktop, your QuickLaunch toolbar, your custom explorer toolbar, etc.) and you have 1-click access to a command prompt on your Linux / Unix host.

Enjoy!

Posted under Apple, Freeware, Linux, Microsoft, Network, Software, WebDev, ZyXel

Ran across this installing Red Hat’s free Linux distribution Fedora Core 9 code named Suplhur. Installed totally vanilla install with the GUI anaconda front end. The box sees the NIC, and can ping within the local subnet of the LAN network, but can’t ping out. BTW, it holds a static IP on the network interface card (NIC). Gets the error:

connect: Network is unreachable error

We need to set a default route. Here’s how:

Looked in /etc/sysconfig/network-scripts for the file route-eth0 but it wasn’t there.

Using vi (you can use whichever text editor you prefer)  I created that file route-eth0, and put in this one line:

defult via 192.168.0.1

(note: 192.168.0.1 is the LAN IP address of my router. Your router IP address may differ. So you should put in whatever the IP addres of your router is, instead. Most Netgear routers and Qwest DSL boradband modems use 192.168.0.1 and Linksys uses 192.168.1.1 and Belkin uses 192.168.2.1 just to name some common ones.)

Then a simple task of restarting the network and testing:

# service network restart

# ping yahoo.com

Success!

Also, I found that the ethernet adapters weren’t starting automatically. Using the GUI taskbar/ Start Menu, I went into System Administration, then into Services, and enabled the “network” service.  Then change runlevel to 3. Ping works so eth0 is up, and that happened at the runlevel change.  Change to runlevel 5, test, and… yeppers, it works.

Posted under Freeware, Linux, Network