Using the
diff
Command
The
diff
(difference) command is used to compare two text
files and find differences between them. The
wc
command can be used to compare files
since it counts lines, words and bytes. It is possible for two files
to have the same line, word and byte counts but have different
characters and words. The
diff
command can actually find the
differences between the files.
| Command Format: |
| diff [option]
file1 file2 |
The output of this command will display
line-by-line differences between two text files. There are two options
with the diff
command; -i and -c.
- The -i option ignores the case of
the letters; for example, A is equal to a.
- The -c option performs a detailed
comparison and produces a listing of differences with three lines
of context. With this option, the output begins with
identification of the files involved and their creation dates.
Following a line of a dozen asterisks
(*), the line numbers of file1 that are to be displayed are listed.
The actual lines from file1 are then displayed, with a minus symbol (-) in front of
those lines that are different from file2. The same display follows as
it applies to file2, with a plus sign (+) for those lines that are different from
file1. Figure
shows the output from the comparison of the fruit and
fruit2 files. Figures
and show
the output from the individual fruit and fruit2 files.
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Interactive
Media Activity
(Flash,
95 kB) |
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Using
wc
and
diff
In this media activity, you are logged in as user2 and your current working directory is: /home/user2. Refer to the Class File Tree Structure by clicking the 'tree' button located on the Menu Bar and type the commands that would accomplish the requested objectives.
Note: Be sure to press enter after each one. Click on step 1 to begin.
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Lab
Activity
(Adobe Acrobat
Reader, 51 kB) |
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File
Information Commands
In this lab,
you will work with various informational commands. These are
important because they allow you to investigate and discover
information about files. You will use commands to help you
determine what type a file is and what application created
it. You will also work with several commands that let you
see the contents of text files and compare them. |
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