1. L2B Second Linux Course
Session4
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2. L2B Second Linux Course
L2B Linux course
 Session outlines:
 Text Processing Tools
 Text Processing Tools Exercises
 VIM
 VIM Exercises
 Basic System Configuration Tools

3. L2B Second Linux Course
L2B Linux course
Text Processing Tools

4. L2B Second Linux Course
L2B Linux course
 Extracting Text
 cat
• One or more files
 less
• Easy to read
• /text
• n/N
• v open an editor
• Used by man command to present man pages

5. L2B Second Linux Course
L2B Linux course
 Extracting Text
 head
• First 10 lines only
• -n change number of lines
 tail
• Last 10 lines only
• -n change number of lines
• -f monitoring the file

6. L2B Second Linux Course
L2B Linux course
 Extracting Text
 cut
• Display specific columns
• -d column delimiter
• -f number of field
• -c cut by characters
– cut -c2-5 /usr/share/dict/words

7. L2B Second Linux Course
L2B Linux course
 Extracting Text
 Grep
• Display lines where a pattern is matched
• -i case-insensitively
• -n print line numbers of matches
• -v print lines not containing pattern
• -AX include the X lines after each match
• -Bx include the X lines before each match

8. L2B Second Linux Course
L2B Linux course
 Tools for Analyzing Text
 wc
• Counts words, lines, bytes and characters
• -l only line count
• -w only word count
• -c only byte count
• -m character count (not displayed)

9. L2B Second Linux Course
L2B Linux course
 Tools for Analyzing Text
 sort
• Sort text and original file is not changed
• -r reverse (descending) sort
• -n numeric sort
• -u (unique) removes duplicate lines
• -t c field separator
• -k X which field
• uniq & uniq -c

10. L2B Second Linux Course
L2B Linux course
 Tools for Analyzing Text
 diff and patch
• diff foo.conf-broken foo.conf-works
• -u better for patchfiles
• Patching
– diff -u foo.conf-broken foo.conf-works > foo.patch
– patch -b foo.conf-broken foo.patch

11. L2B Second Linux Course
L2B Linux course
 Tools for Analyzing Text
 aspell
• Interactively spell-check files:
– aspell check letter.txt
• Non-interactively list mis-spelled words in
– Only reads data from standard input
– aspell list < letter.txt

12. L2B Second Linux Course
L2B Linux course
 Tools for Manipulating Text
tr and sed

13. L2B Second Linux Course
L2B Linux course
 Tools for Manipulating Text
 Tr
• Converts characters in one set to corresponding
characters in another set
• Only reads data from STDIN
• tr 'a-z' 'A-Z' < lowercase.txt

14. L2B Second Linux Course
L2B Linux course
 sed (stream editor)
 search/replace operations on a stream of text
 Normally does not alter source file
 -i to alter source file
 -i.bak to back-up and alter source file

15. L2B Second Linux Course
L2B Linux course
 sed Examples
 sed 's/dog/cat/i' pets
 sed 's/dog/cat/g' pets
 sed '1,50s/dog/cat/g' pets
 sed '/digby/,/duncan/s/dog/cat/g' pets
 sed -e 's/dog/cat/' -e 's/hi/lo/' pets

16. L2B Second Linux Course
L2B Linux course
 Characters for Complex Searches
 ^ represents beginning of line
 $ represents end of line
 Character classes as in bash:
• [abc], [^abc]
• [[:upper:]], [^[:upper:]]
 Used by: grep, sed, less, others

17. L2B Second Linux Course
L2B Linux course
VIM

18. L2B Second Linux Course
L2B Linux course
 VIM Advantages:
 Speed: Do more with fewer keystrokes
 Simplicity: No dependence on mouse/GUI
 Availability: Included with most Unix-like OSes
 Disadvantages
 Difficulty: Steeper learning curve than simpler
editors

19. L2B Second Linux Course
L2B Linux course
 Three main modes:
 Command Mode (default): Move cursor,
cut/paste text
 Insert Mode: Modify text
 Exit Mode: Save, quit, etc

20. L2B Second Linux Course
L2B Linux course
 First steps with vim
 vim filename(command mode)
 Insert mode
• I at the cursor
• A append to end of line
• I insert at beginning of line
• o insert new a line (below)
• O insert new line (above)
 Exit mode
• :w writes (saves) the file to disk
• :wq writes and quits
• :q! quits, even if changes are lost

21. L2B Second Linux Course
L2B Linux course
 Command Mode
 Right Arrow moves right one character
 5, Right Arrow moves right five characters
 Arrow Keys, h, j, k, l (the same as arrows)
 w, b Move by word
 ), ( Move by sentence
 }, { Move by paragraph
 xG Jump to line x
 gg Jump to the first line
G Jump to the last line

22. L2B Second Linux Course
L2B Linux course
 Command Mode
 As in less
• /, n, N
 As in sed
 The selected line only
• :1,5s/cat/dog/
 All of the entire file
• :%s/cat/dog/gi

23. L2B Second Linux Course
L2B Linux course
 Command Mode
 Line
• cc
• dd
• yy
 Letter
• cl
• dl
• yl

24. L2B Second Linux Course
L2B Linux course
 Command Mode
 Word
• cw
• dw
• yw
 Sentence ahead
• c)
• d)
• y)

25. L2B Second Linux Course
L2B Linux course
 Command Mode
 Sentence behind
• c(
• d(
• y(
 Paragraph above
• c{
• d{
• y{

26. L2B Second Linux Course
L2B Linux course
 Command Mode
 Paragraph below
• c}
• d}
• y}
u undo
 Ctrl-r redo
 U undo all changes to the last modified line

27. L2B Second Linux Course
L2B Linux course
 Command Mode
 v starts character-oriented highlighting
 V starts line-oriented highlighting
 Visual keys used with movement keys:
• w, ), }, arrows
 Highlighted text can be
• Deleted
• Yanked
• Changed
• Filtered
• search/replaced, etc.

28. L2B Second Linux Course
L2B Linux course
 Command Mode
 Ctrl-w, s splits the screen horizontally
 Ctrl-w, v splits the screen vertically
 Ctrl-w, Arrow moves between windows
 Ctrl-w twice, Arrow moves between windows
 To search for help inside vim convert to the
exit mode and ask for help by running the
following
• :help

29. L2B Second Linux Course
L2B Linux course
 Configuring vi and vim
 :set
• :set number
• :set all
• :set number (:se nu)
• :set nonumber (:se nonu)
• :set ignorecase (:se ic)
• :set noignorecase (:se noic)
• :set showmatch (:se sm)
• :set noshowmatch(:se nosm)
• :set autoindent
• :set noautoindent

30. L2B Second Linux Course
L2B Linux course
 Configuring vi and vim
 :help
 :help something
 :set
• :set textwidth=3
• :set textwidth=0
• :set wrapmargin=10
• :set wrapmargin=0
 ~/.vimrc
 vimtutor

31. L2B Second Linux Course
L2B Linux course
Basic System
Configuration Tools

32. L2B Second Linux Course
L2B Linux course
 Introduction
 Network interfaces are named sequentially:
eth0, eth1, etc
 Multiple addresses can be assigned to a
device with aliases
 Aliases are labeled eth0:1, eth0:2, etc.
 Aliases are treated like separate interfaces
 View interface configuration with :
ifconfig [ethX]
 Enable interface with ifup ethX
 Disable interface with ifdown ethX

33. L2B Second Linux Course
L2B Linux course
 Graphical Network Configuration
 system-config-network
 System > Administration > Network
 Network Configuration Files For Devices
 /etc/sysconfig/network-scripts/ifcfg-ethX
 Complete list of options in
/usr/share/doc/initscripts-*/sysconfig.txt

34. L2B Second Linux Course
L2B Linux course
 Example Of Dynamic Configuration
 DEVICE=ethX
 HWADDR=0:02:8A:A6:30:45
 BOOTPROTO=dhcp
 ONBOOT=yes
 Type=Ethernet

35. L2B Second Linux Course
L2B Linux course
 Example Of Static Configuration
 DEVICE=ethX
 HWADDR=0:02:8A:A6:30:45
 IPADDR=192.168.0.254
 NETMASK=255.255.255.0
 GATEWAY=192.168.2.254
 ONBOOT=yes
 Type=Ethernet

36. L2B Second Linux Course
L2B Linux course
 Network Configuration Files and Other
Global Network Settings
 /etc/sysconfig/network
• NETWORKING=yes
• HOSTNAME=server1.example.com
• GATEWAY=192.168.2.254

37. L2B Second Linux Course
L2B Linux course
 DNS configuration
 Server address is specified by dhcp or in
/etc/resolv.conf
• nameserver 192.168.0.254
• nameserver 192.168.1.254

38. L2B Second Linux Course
L2B Linux course
 Setting the System's Date and Time
 GUI:
• system-config-date
• System->Administration->Date & Time
 CLI: date [MMDDhhmm[[CC]YY][.ss]]
• date 01011330
• Date 010113302007.05
• Date 12312359
• Date 123123592007
• Date 01010101.01

39. L2B Second Linux Course
L2B Linux course
 Scripting
 Taking input with positional parameters
• $1
• $2
• $3
• $4, etc.
• $*
• $#

40. L2B L2B Second Linux
Course Second Linux
L2B Linux course
Course
 Scripting
 Taking input with the read command
• read x
• read -p "Enter a filename: " file

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