Archive for July, 2008

• TECHPULP | How to use Secure Shell (SSH)
  Secure shell (SSH) is a replacement for telnet. telnet uses plain text protocol so a man in the middle can see what is being exchanged between client and server including sensitive information like passwords. A more sophisticated hacker can even...
• TECHPULP | Seamless directory navigation in bash
  It is time (and brain) consuming to remember and type the directory path if you require to move across directories frequently. You can save some time and energy with three in-built commands supported by bash. They are pushd, popd and...

• TECHPULP | PHP Page Redirection
  This article explains how to redirect to another page using PHP. You can use header function in the beginning of PHP script to inform browser about page redirection. Basically this writes Hyper Text Transfer Protocol(HTTP) header with the field Location....
• TECHPULP | How to resolve “Address already in use” error with bind system call
  To get rid of “Address already in use” error with bind system call, SO_REUSEADDR socket option should be set before invoking bind. This makes operating system to allow the socket to bind if there is no active socket bound to...

• TECHPULP | Find local IP address and local port number using getsockname
  The getsockname function can be used to find the local port used by a given socket. It is valid to use this function only if the socket is already using a local port number. i.e A server socket which invoked...
• TECHPULP | Find peer IP address and port number using getpeername
  The getpeername function can be used to retrieve the peer IP address and port number on a given socket. For this to work, the socket should have a valid TCP connection established. Typically this is used by server to find...

• TECHPULP | How to extract files from RPM
  All the files present in a RPM file can be extracted using rpm2cpio and cpio utilities. The rpm2cpio command is used to convert RPM to cpio compatible archive and cpio command can be used to extract files from the archive....
• TECHPULP | Identify processes that have open sockets
  The lsof can be used to find the list of processes that have active sockets open. Let us see the list of current TCP connections using netstat command. [liz@techpulp ~]# netstat -nt Active Internet connections (w/o servers) Proto Recv-Q Send-Q...

• TECHPULP | Linux file compression tools/utilities
  Linux has various types of compression and decompression tools like tar, gzip, bzip2, zip and compress. This article describes practical usage of these utilities. tar and untar tar command operates on one or more files or directories and creates an...
• TECHPULP | Print first N characters of a string using printf
  #include <stdio.h> int main(int argc, char *argv[]) { char *p = "My Name is Neo"; printf("First 5 bytes of string is '%.5s'\n", p); return 0; } Result [neo@techpulp ex]# gcc example.c -o example [neo@techpulp ex]# ./example First 5 bytes of...