| Use the grep
(Global Regular Expression Print) command
to search a file or the output of a command for a specified text
string. A string is one or more characters; it can be a character, a
word, or a sentence. A string can include white space or punctuation
if enclosed in quotations. The grep
command searches a file for a character string and prints all lines
that contain that pattern to the screen. The grep
command is frequently used as a filter with other commands. For
instance, you can issue the ps
(process status) command and look for all occurrences of a specific
process. The grep
command is case-sensitive. You must match the pattern with respect to
uppercase and lowercase letters, unless you use the -i option,
which ignores the case. The -v option searches for all lines
that do not match the string specified.
Figure
shows the basic format
of the grep
command and Figure
shows examples of how to search lines in a
file or standard output.
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Interactive
Media Activity
(Flash,
90 kB) |
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Searching
for strings
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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