A glass case of thoughts » linux

linux: handy commands

Jyotsna — Wed, 18 Mar 2009 06:10:08 +0000

copy files from one linux server to another through shell

$ scp user@from_computer:dir/filename user@to_computer:dir/filename

open shell to another linux machine from one through shell
```
$ ssh user@to_computer
```
Prints the owner of every file or directory in the current directory. The AWK syntax is simply “print the 3rd field in every line of data”
```
ls -l | awk '{print $3}'
```
To get the owner of only one file (filename):
```
ls -l | grep filename | awk '{print $3}'
```
To compress a folder:
```
zip -r target.zip folder/
```
User creation
```
useradd username
```
Change user password
```
passwd username
```
Add user to a group
```
usermod -g grpname username
```

Import SQL script to an empty mysql database

mysql -u root -p database_name < script_file.sql

Unfreeze vi editor in terminal window when frozen because of ctrl+S action
```
press ctrl+q
```
Reboot linux server remotely
```
sudo reboot
```
Shut down linux server remotely
```
sudo shutdown -h now
```

Kill a process

top
type k to kill a process. You will be prompted for the PID of the task, and the signal to send to it. For a normal kill, send signal 15. For a sure, but rather abrupt, kill, send signal 9. The default signal, as with kill(1), is 15, SIGTERM. This command is not available in secure mode.

To close port – 80 in following example
```
fuser -k 80/tcp
```

linux how to: replicate svn repository

Jyotsna — Sat, 28 Feb 2009 11:27:22 +0000

Task at hand:

I have a repository on one of the linux server. As a part of upgradation process, we decided to move the SVN server to a newer better linux infrastructure. Task at hand is to replicate the svn repositories on new server.

Solution:

Create dump for existing repository
```
svnadmin dump /path/to/repo > /path/to/dump/folder/myrepo.dump
```
This command creates a .dump file and shows the revisions being dumped as it progresses
Transfer the dump file to new server. This can be accomplished through SSH / FTP connection or a simple scp command as:

scp /path/to/dump/folder/myrepo.dump user@new_server:/path/to/dump/folder/myrepo.dump

Log into new server and switch to the directory where you want to place your replicated svn repository. Then, create an empty svn repository
```
svnadmin create myrepo
```

Load empty reposity with dump file

svnadmin load myrepo < /path/to/dump/folder/myrepo.dump

Define group ownership and permission

chown -R :all myrepo
chmod -R 770 myrepo

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IIS SSL and linux openSSL

Jyotsna — Mon, 19 Jan 2009 12:02:36 +0000

I have a .NET web service that I want to be accessed over https rather than http. Problem is HOW !!

Solution:

Activate SSL on web server (IIS)
- Follow steps 1 through 4 of this very useful blog by Eric Longman
Specify the file for which SSL is required
- Through inetmgr, browse to the file (in my case the .asmx file). Right click -> Properties -> File Security -> Secure Communications -> Edit
- Check Require SSL Channel (SSL)

And you should be done.

Related useful article:
CONSUMING WEBSERVICES OVER HTTPS (SSL)

How to make SVN remember password

Jyotsna — Sat, 06 Dec 2008 09:54:24 +0000

Who is this post for?

This post is for anyone who wants a step by step guide to accomplish any of the following

Make a SVN client like tortoise svn remember password
Make linux server remember your password when logging through putty

Tools you need:

Putty
Puttygen

What you need to do:

Using putty – login to linux server. change directory to ~/.ssh/ by typing following command

cd ~/.ssh

Type command
```
ssh-keygen -b 1024 -t dsa
```
and press enter. Do not enter a passphrase. Hit enter when prompted for one. Same for the filename. default filename = id_dsa and id_dsa.pub. id_dsa is the private key file and id_dsa.pub is the public key file.
type command
```
cat ~/.ssh/id_dsa.pub
```
Copy the output to the clipboard by selecting the output by mouse.
Type command
```
vi ~/.ssh/authorized_keys
```
Hit i to enter Insert mode and then paste your public key (if there is already a key in this file, move to the bottom before pasting). Hit the ESC key to leave Insert mode and type :wq and hit enter to save and exit vi editor.
Using ftp download your key files – both private and public

In order to use the private key we get from the server, we have to convert it to a putty format. This is because the private key file format is not specified by some standard body. We can accomplish this using puttygen. Open Puttygen

In the tree structure on left, choose conversion -> import key -> choose the private key file downloaded from ftp

Choose to save private key. Choose path and save the file as anything.ppk

Run Putty. Specify parameters
- Session->HostName: Hostname or IP Adress of your server
- Session->Protocol: SSH
- Session->Saved Sessions: MyConnection
- SSH->Prefered SSH Protocol version: 2
- SSH->Auth->Private Key file for auth: $PATH$mykey.PKK (replace $PATH$ with real path to the mykey.PKK file)
Go back to Session tab and hit “save” button. You will see “MyConnection” in the list of available connections.

Next click “open” and you should see a telnet login prompt. Use “myuser” as username (without double quotes of course) and if everything is OK, you don’t have to provide a password to your system. If the system still requires a password, something went wrong.

Now that linux server and putty manage to remember your password, you need an application client to use it. In this case it is SVN client e.g. tortoise svn. Go to TortoiseSVN->RepoBrowser and specify a URL like this:
```
svn+ssh://myuser@MyConnection/usr/local/repos
```
…where MyConnection is the putty session name and /usr/local/repos is my svn repository on linux server

And you are done …

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