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A Guide to Unix Using Linux Fourth Edition

A Guide to Unix Using Linux Fourth Edition. Chapter 8 Exploring the UNIX/Linux Utilities. Objectives. Understand many of the UNIX/Linux utilities that are available and how they are classified Use the dd utility to copy and convert files Monitor hard disk usage Use system status utilities

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A Guide to Unix Using Linux Fourth Edition

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  1. A Guide to Unix Using Linux Fourth Edition Chapter 8 Exploring the UNIX/Linux Utilities

  2. Objectives • Understand many of the UNIX/Linux utilities that are available and how they are classified • Use the dd utility to copy and convert files • Monitor hard disk usage • Use system status utilities • Monitor and manage processes • Check the spelling of text in a document A Guide to Unix Using Linux, Fourth Edition

  3. Objectives (continued) • Use the cmp command to compare the contents of two files • Format text to create and use a man page • Use the dump command to back up a system • Send and receive e-mail • Use basic network commands and utilities A Guide to Unix Using Linux, Fourth Edition

  4. Understanding UNIX/Linux Utilities • UNIX/Linux utilities are classified into: • File processing • System status • Networking • Communications • Security • Programming • Source code management • Miscellaneous A Guide to Unix Using Linux, Fourth Edition

  5. Classifying UNIX/Linux Utilities • Several categories • Network tasks • Programming tasks • File-processing utilities • Make up the largest category • Display and manipulate files A Guide to Unix Using Linux, Fourth Edition

  6. A Guide to Unix Using Linux, Fourth Edition

  7. A Guide to Unix Using Linux, Fourth Edition

  8. Classifying UNIX/Linux Utilities (continued) A Guide to Unix Using Linux, Fourth Edition

  9. Classifying UNIX/Linux Utilities (continued) A Guide to Unix Using Linux, Fourth Edition

  10. Classifying UNIX/Linux Utilities (continued) A Guide to Unix Using Linux, Fourth Edition

  11. Classifying UNIX/Linux Utilities (continued) A Guide to Unix Using Linux, Fourth Edition

  12. Classifying UNIX/Linux Utilities (continued) A Guide to Unix Using Linux, Fourth Edition

  13. Using the dd Command A Guide to Unix Using Linux, Fourth Edition

  14. Checking Hard Disk Usage • Basic strategies used to maintain adequate free space: • Be vigilant against running dangerously low on free space • Use df command • Watch for conspicuous consumption • Use du command • Follow a routine schedule for “garbage” collection and removal • Use a combination of find and rm commands A Guide to Unix Using Linux, Fourth Edition

  15. Using the df Utility • If entered without specifying file system, shows information for all mounted file systems A Guide to Unix Using Linux, Fourth Edition

  16. Using the df Utility (continued) A Guide to Unix Using Linux, Fourth Edition

  17. Using the du Utility • With no options, report is based on all file usage • Starts at current directory • By default, output is in number of 512-byte blocks A Guide to Unix Using Linux, Fourth Edition

  18. A Guide to Unix Using Linux, Fourth Edition

  19. Removing Garbage Files • Garbage files are temporary files that lose their usefulness after several days • Remove to free space • Example: core files, compilation output • Core file: created when executing program attempts to do something illegal • Example: accessing another user’s memory • Use find and rm to find and remove garbage files: find . "(" -name a.out -o -name core ")" -exec rm {} \; A Guide to Unix Using Linux, Fourth Edition

  20. Using System Status Utilities • System status commands reflect system’s performance • You can redirect the output of these commands to a file • File can later be: • Printed • Forwarded to system administrator and system tune-up specialists A Guide to Unix Using Linux, Fourth Edition

  21. Using the top Command A Guide to Unix Using Linux, Fourth Edition

  22. Using the uptime Command • Example: use it to track how long system has been up since last problem requiring a reboot A Guide to Unix Using Linux, Fourth Edition

  23. Using the free Command • Swap space is disk space that acts like an extension of memory A Guide to Unix Using Linux, Fourth Edition

  24. Using the free Command (continued) A Guide to Unix Using Linux, Fourth Edition

  25. Forwarding top and free Output • You may forward output of top and free to a computer support person for analysis • Example: top n 3 > topdata lpr topdata A Guide to Unix Using Linux, Fourth Edition

  26. Managing Processes • When you run a program, it starts one or more processes • Processes are identified through a unique number • Process id or PID • UNIX and Linux offer utilities to: • Manage how a program is run • Monitor processes • Kill processes A Guide to Unix Using Linux, Fourth Edition

  27. Running Processes in the Background • UNIX/Linux is a multitasking OS • You can run processes in the background • To run a process in background: • Append the & character • Example: top& A Guide to Unix Using Linux, Fourth Edition

  28. Monitoring Processes • If used with no options, shows a list of processes associated with the current login session A Guide to Unix Using Linux, Fourth Edition

  29. Monitoring Processes (continued) A Guide to Unix Using Linux, Fourth Edition

  30. Killing Processes • System administrator may want to kill a user’s process because: • Associated program is malfunctioning • Associated program is using too many system resources • A user may want to kill a process that is running in the background A Guide to Unix Using Linux, Fourth Edition

  31. Checking the Spelling of a Document • ispell • Scans a text document • Displays errors on screen • Suggests other words with similar spellings as replacements for unrecognized words A Guide to Unix Using Linux, Fourth Edition

  32. Checking the Spelling of a Document (continued) A Guide to Unix Using Linux, Fourth Edition

  33. Comparing Files • If the contents are identical, there is no output • Otherwise, output specifies first byte (character) that is different between the files A Guide to Unix Using Linux, Fourth Edition

  34. Formatting Text in UNIX/Linux A Guide to Unix Using Linux, Fourth Edition

  35. Archiving and Backing Up Files • Good practice to periodically archive or back up files • You can back up files to: • CD, DVD, tape, or another removable medium • For backup to CD/DVD, consider using a GUI tool • Example: GNOME CD/DVD Creator GUI software • Part of Nautilus A Guide to Unix Using Linux, Fourth Edition

  36. Using the dump Command A Guide to Unix Using Linux, Fourth Edition

  37. Using the restore Command • Restores from a backup medium created via dump • By default, copies back to current working directory • Example: restore -r -f /dev/st0 A Guide to Unix Using Linux, Fourth Edition

  38. Using mail to Send Mail • Press Ctrl+d to exit the text mode • To leave the mail utility, type q and press Enter A Guide to Unix Using Linux, Fourth Edition

  39. Using mail to Send Mail (continued) A Guide to Unix Using Linux, Fourth Edition

  40. Using mail to Send Mail (continued) A Guide to Unix Using Linux, Fourth Edition

  41. Using Networking Utilities • UNIX and Linux offer many utilities to accommodate a connection to the network • ifconfig • ping • traceroute • netstat A Guide to Unix Using Linux, Fourth Edition

  42. Using the ifconfig Utility • Internet Protocol (IP) is used to help ensure that information on a network goes to the right place • IP address uses a dotted decimal notation • Consists of four octets separated by periods • Identifies a computer/device and the network it is on A Guide to Unix Using Linux, Fourth Edition

  43. Using the ping Utility • Examples: • ping rbrown@xxx.com • ping redhat.com A Guide to Unix Using Linux, Fourth Edition

  44. Using the traceroute Utility • Sample use: • To ensure your computer is connected and working • To ensure your network is working from point to point A Guide to Unix Using Linux, Fourth Edition

  45. Using the netstat Utility • Information provided by netstat includes: • Network protocol communications • Network connections established by host computer • Network routing information • Information about remotely logged computers A Guide to Unix Using Linux, Fourth Edition

  46. Sharing Resources Using Network File System • Network File System (NFS): used for resource sharing over a network • Once partition is mounted, access is transparent • mount bluefin:/home/mpalmer/shared /mnt/shared • Three versions typically supported: • NFSv2, NFSv3, and NFSv4 • Client and host communicate via RPCs • RPC: Remote Procedure Call • Portmap service: • Handles RPC request to mount a partition • Makes computer act like a server for NFS file access A Guide to Unix Using Linux, Fourth Edition

  47. Sharing Resources Using Network File System (continued) • To start a service, use service command • service portmap • NFS security handled through entries in: • /etc/hosts.allow, /etc/hosts.deny, and /etc/exports /home/mpalmer/shared 192.168.0.72(ro) 192.168.0.84(ro) /home/mpalmer/docs 192.168.0.72(rw) 192.168.0.41(rw) A Guide to Unix Using Linux, Fourth Edition

  48. Accessing Microsoft Windows Systems Through Samba • Samba: utility that uses the SMB protocol • Server Message Block (SMB) is used by Windows systems for sharing folders and printers • Typical configuration file: • /etc/samba/smb.conf file • Some ways to access Windows shared drives: • Network Servers  Windows Network • Computer  More Applications  Network Servers File Browser  Windows Network • K menu  KNOPPIX  Utilities  Samba Network Neighborhood A Guide to Unix Using Linux, Fourth Edition

  49. Summary • Some useful utility programs are: • dd, df, and du for converting files, checking free space, and checking disk usage, respectively • find and rm can be used together to remove garbage files • top and free provide detailed views of system internals • uptime shows how long a system has been up • ps and kill to display and kill processes • ispell to check for spelling errors in a file • nroff, troff, and groff for formatting output A Guide to Unix Using Linux, Fourth Edition

  50. Summary (continued) • Other useful utility programs are: • dump and restore to archive and restore backups • mail to send and retrieve mail • ifconfig, ping, traceroute, and netstat for viewing information about the network connection and for troubleshooting the connection • Services for sharing resources over network: • Network File System (NFS) to access resources in another UNIX/Linux computer • Samba to access resources in a Windows computer A Guide to Unix Using Linux, Fourth Edition

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