Linux OPS Practice-August 27, 2015 Course assignments

1. summarize the use of the commands involved in this course and the relevant examples show:

Chmod,chgrp,umask,chown,grep,egrep

2. summarize basic regular expressions and extended regular Expressions

Format:

grep [OPTIONS] PATTERN [FILE ...] ：

Options:

--color=auto: The matching string is highlighted; \ \ can be--color directly as the default color

-V: Display mode does not match rows

-I: Ignore character case

-O: Show only strings that can be matched to a pattern

-Q: Silent mode

-E: Using extended regular expressions

1. Basic regular Expression meta-character

.: Matches any single character

*: Matches any of its preceding characters any time

. *: Denotes any character of any length

[]: Any single character within the specified range

[^]: characters other than the specified character

X\{m,n\}: Indicates that the preceding character X appears at least m times, at most n times

X\{m\}: Indicates exact match m times

Note: In the basic regular expression? To be used, the escape character must be added to the front

^: Beginning of line anchor

$: End of line anchor character

\ (\): Group reference

\1: Represents the contents of the first set of parentheses

\2: Represents the contents of the second set of parentheses;

\w: Equivalent to [0-9a-za-z]

\< \b: The first anchor of the word; the left side of the pattern used to denote the word;

\>, \b: the ending anchor; the right side of the pattern used to represent the word

^$: Blank Line

\?:0 or 1 times

\+:1 or more

The metacharacters of the extended regular expression is basically the same as that of the basic regular expression, and the following are the differences:

\ (\) becomes only used () to denote

\{\} to be represented only with {}

+: Indicates that the character before it matches at least once

|: or meaning; for example a|b means A or b is ok

3. display the lines in the/etc/passwd file that end with bash

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4. display the two-digit or three-digit number in the/etc/passwd file

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5. display lines with ' LISTEN ' followed by 0, one or more whitespace characters in the ' netstat-tan ' command result

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6. Add User bash, Testbash, basher, and Nologin user (Nologin user's shell is/sbin/nologin), then find out/etc/ A row in the passwd file that has the same user name as its shell name

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7. Display the default shell and UID of root, CentOS, or User1 user on the current system (please create these users beforehand, if not present)

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8, find a word in the/etc/rc.d/init.d/functions file (the middle of the word can be underlined) followed by a set of parentheses line

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9, use echo to output a path, and then egrep find its path base name; Further use Egrep to remove its directory name

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Find the number between 1-255 in the result of the ifconfig command execution

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Linux OPS Practice-August 27, 2015 Course assignments