Chapter Eight Exploring the UNIX Utilities

2 Lesson A Using the UNIX Utilities

3 Objectives Understand what UNIX utilities are available and the classifications of utilities Determine hard disk usage and available free space Display the CPU status and internal memory usage

4 Understanding UNIX Utilities UNIX utilities let you create and manage files, run programs, produce reports, and generally interact with the system They also offer a full range of services that let you monitor and maintain the system and recover from a wide range of errors Utility programs are vital for working through an OS and new utilities are continually being added in order to make UNIX run more efficiently

5 Understanding UNIX Utilities UNIX utilities are classified into seven major function areas dictated by user needs –File processing –System status –Networking –Communications –Programming –Source code management –Miscellaneous

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14 Lesson B Working with the Text-Formatting File Utilities

15 Objectives Check the spelling of text in a document Use the cmp command to compare the contents of two files Format text to create a man page Use the groff utility to test a man page you have created Use the man utility to view a man page you have created

16 Checking the Spelling of a Document Ispell scans a document, displays errors on the screen and suggests alternative spellings

17 Comparing Files Use the cmp utility to compare the contents of two files, and report the first difference between them The cmp command displays the character position and line number of this difference If there are no differences, the cmp command displays nothing

18 Formatting Text in UNIX Text formatting in UNIX involves preparing a text file with embedded typesetting commands and then processing the marked-up text file with a computer program UNIX’s nroff and troff commands are often used to process the embedded typesetting commands to format the output An embedded code is a special sequence of characters that is included with the regular text of the file

19 Formatting Text in UNIX Linux introduced groff, which implements the features of both nroff and troff

20 Formatting Text in UNIX Groff can be used to produce a man page that contains the standard man page sections

21 Formatting Text in UNIX Man pages are made available to others by having a supervisor user copy it to one of the man page directories

22 Chapter Summary UNIX utilities are classified into seven major functional areas dictated by user needs: file processing, networking, communications, system status, programming, source code, management, and miscellaneous tasks Utility programs are distinguished from other OS programs, because they are add-ons and not a part of the UNIX shells Because utility programs are executed by entering names on the command line, they are commonly referred to as commands

23 Chapter Summary The df utility checks and reports on free disk space The du command checks for disk usage Use the find command to retrieve wasteful files and then use the rm command to remove them The top and free utilities provide detailed views of the “internals” of the system Redirect output of the top and free commands to a disk file to use as input for a report to the system administrator

24 Chapter Summary Run a program in the background by appending the & operator to the end of a command line The ps command displays all processes currently running The kill command terminates a specific process The utility that checks spelling, ispell, scans a document for typing errors

25 Chapter Summary Text formatting involves embedding typesetting commands in a file, and then processing the the marked-up file with a program that generates commands for the output device The text containing the embedded typesetting commands is processed by a program like nroff and troff that formats the output Linux introduced groff, which implements the features of both nroff anf troff Those who have supervisor privileges most often create man pages