18CS56 MODULE 2 UNIX PROGRAMMING VTU NOTES

 File attributes and permissions:

The ls command with options. Changing file permissions: the relative and absolute permissions changing methods. Recursively changing file permissions. Directory permissions.

The shells interpretive cycle:

Wild cards. Removing the special meanings of wild cards. Three standard files and redirection.

Connecting commands:

Pipe. Basic and Extended regular expressions. The grep, egrep. Typical examples involving different regular expressions.

Shell programming:

Ordinary and environment variables. The .profile. Read and readonly commands. Command line arguments. exit and exit status of a command. Logical operators for conditional execution. The test command and its shortcut. The if, while, for and case control statements. The set and shift commands and handling positional parameters. The here ( << ) document and trap command. Simple shell program examples.