Wednesday, May 23, 2001

Repairing a Corrupted .PST file in Microsoft Outook

1. Run Scanpst.exe.
2. Choose the corrupted .pst file by browsing it.
3. Do repair.

Saturday, May 12, 2001

Find Techniques on UNIX

Find a file with given name
find /home/sriram -name core

Find files larger than 1MB
find /home/sriram -size +1000000c -print

Find files larger than 10 KB, but less than 32 KB
(The . denotes current directory)
find . -size +10000c -size -32000c -print

Find files that were modified less than 8, more than 6 days ago
find . -mtime +6 -mtime -8 -print

Find files that were modified exactly 7 days old
find . -mtime 7 -print

Find files that were last accessed more than 30 days ago
find . -atime +30 -print

To delete files older than 200 days
find /home/sriram/ -mtime +200 -exec rm {} \;

find can be used in many other ways. Here are a couple of examples:

  1. To find all subdirectories in your home directory:
    find ~ -type d
  2. To remove all files containing the string trivial in your home directory and subdirectories (and be asked before deleting each file):
    find ~ -name \*trivial\* -exec rm -iv {} \;
  3. To find all files accessed 3 minutes ago:
    find ~ -amin 3
  4. To find all files whose status was changed 5 minutes ago:
    find ~ -cmin 5
  5. To find all empty files:
    find ~ -empty

Thursday, May 03, 2001

How UNIX is Organised

The UNIX system is functionally organized at three levels:

  • The kernel, which schedules tasks and manages storage;
  • The shell, which connects and interprets users' commands, calls programs from memory, and executes them; and
  • The tools and applications that offer additional functionality to the operating system.

The three levels of the UNIX system: kernel, shell, and tools and applications.

The kernel

The heart of the operating system, the kernel controls the hardware and turns part of the system on and off at the programer's command. If you ask the computer to list (ls) all the files in a directory, the kernel tells the computer to read all the files in that directory from the disk and display them on your screen.

The shell

There are several types of shell, most notably the command driven Bourne Shell and the C Shell (no pun intended), and menu-driven shells that make it easier for beginners to use. Whatever shell is used, its purpose remains the same -- to act as an interpreter between the user and the computer.

The shell also provides the functionality of "pipes," whereby a number of commands can be linked together by a user, permitting the output of one program to become the input to another program.

Tools and applications

There are hundreds of tools available to UNIX users, although some have been written by third party vendors for specific applications. Typically, tools are grouped into categories for certain functions, such as word processing, business applications, or programming.