Chapter%20Eight

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Chapter Eight

• Exploring the UNIX Utilities

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Lesson A

• Using the UNIX Utilities

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Objectives

• Understand what UNIX utilities are available and
  the classifications of utilities
• Make a bootable floppy disk to boot the system in
  case of an emergency
• Duplicate files on a floppy disk

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Objectives

• Determine hard disk usage and available free
  space
• Locate and remove unnecessary files from the hard
  disk
• Display the CPU status and internal memory usage

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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

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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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Using theFile Processing Utilities

• The dd command allows you to copy a file and
  change the format of the destination file
• The dd command possesses a rich set of options
  that allow it to handle copies when other methods
  are inappropriate
• An advantage to using the dd command over cp is
  that all users, not just the administrator, can
  copy files to and from the floppy drive

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Making a Bootable Floppy Disk

• It is a good idea to make a bootable floppy disk,
  because a computer problem may prevent you from
  starting UNIX from the system
• To make a bootable floppy disk, use four utility
  programs rdev, mkfs, fdformat, dd

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Making a Bootable Floppy Disk

• The rdev command queries and sets the root
  device, which is the hard disk partition that
  houses UNIXs root file system
• The mkfs command builds a UNIX or Linux file
  system on a device such as a floppy disk or a
  hard disk partition
• The fdformat command formats a floppy at low
  levels to ensure the media is clear of defects
  and is writeable
• Use the dd command to make a back-up copy of a
  floppy disk

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Making a Bootable Floppy Disk
The file system type determines how UNIX reads
and writes information from or onto the device
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Making a Bootable Floppy Disk
After creating a bootable disk, it can be used to
start the system
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Checking Hard Disk Usage

• To maintain adequate hard disk free space, use
  these strategies
• Be vigilant against running dangerously low on
  free space by using the df command
• Watch for conspicuous consumption using the du
  command
• Follow a routine schedule for garbage
  collection and removal by using the rm command

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Using the df Utility
The df utility reports on the status of1024-byte
blocks
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Using the df Utility
The df h option causes the block data to display
in human-readable form
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Using the df Utility
The du utility summarizes disk usage, expressed
in 512-byte blocks (default) or by the number of
bytes(-b option)
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Using the df Utility
...the second screen resulting from using more
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Removing Garbage Files

• Garbage files are temporary files that lose their
  usefulness after several days
• Two examples of garbage files are core files
  (named core) and a.out files
• Use the find command to assist you in locating
  these files and the rm command to remove them

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Applying System Status Utilities

• System engineers primarily use the data related
  to system status
• One of the most effective utilities for auditing
  system performance is the top command
• The top command displays a listing of the most
  CPU-intensive tasks, such as the processor state

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Applying System Status Utilities
The top utility run without any options specified
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Applying System Status Utilities
To kill the top utility process, enter k and
specify the PID to terminate
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Applying System Status Utilities
You cannot killthe top utility when run in
secure mode
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Applying System Status Utilities
The free utility displays the amount of free and
used memory in the system
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Applying System Status Utilities
The ps command shows a list of processes
associated with the current login session that
are currently running
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Applying System Status Utilities
The ps command with the A option shows a list of
all system processes currently running
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Lesson B

• Working with the
• Text-Formatting File Utilities

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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

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

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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
• UNIXs 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

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Formatting Text in UNIX
Linux introduced groff, which implements the
features of both nroff and troff
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Formatting Text in UNIX
Groff can be used to produce a man page that
contains the standard man page sections
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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
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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

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Chapter Summary

• The dd command possesses a rich set of options
  that allow it to handle copies when other copying
  methods fail
• To make a bootable floppy disk, use four utility
  programs rdev, mkfs, fdformat, and dd
• The rdev command queries and sets the root device
• The fdformat command performs a low-level format
  on a floppy disk
• The mkfs utility sets up a file system

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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

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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

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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