How to use scan command to match mode

The scan command can search for patterns in files. Syntax: scan [Options] Mode [File...]. Options include: -l (print line numbers only), -n (print line numbers and matching lines), -q (not print output), and -e (interpretation mode is an extended regular expression). The pattern can be a basic string, a regular expression, or an awk program. Steps: Open the terminal window, enter the scan command and press Enter.

How to match patterns using scan command

scan command is a powerful Unix command that allows you to search for patterns in files. It works by scanning the input text and finding lines that match the specified pattern.

grammar

scan [选项] 模式[文件...]

Options

• -l : Only the line number of the matching line is printed.
• -n : Print line number and matching line.
• -q : No output is printed, only the exit status is returned.
• -e : interprets the pattern as an extended regular expression.

model

The mode can be any of the following:

• Basic string: directly match strings in text (case insensitive).
• Regular expressions: Use regular expression notation to match complex patterns.
• awk program: Use the awk programming language to write expressions to match rows.

use

To use the scan command, follow these steps:

1. Open a terminal window.
2. Type the scan command followed by the options, patterns, and file list.
3. Press Enter.

Example

The following example shows how to use the scan command:

• Match a specific string:

 <code>scan "error" system.log</code>

• Find numbers using regular expressions:

 <code>scan -l "[0-9] " numbers.txt</code>

• Use the awk program to find lines containing "warning":

 <code>scan -n 'index($0, "警告") != 0' error.log</code>

Exit status

The scan command returns the following exit status:

• 0 : A match was found.
• 1 : No match was found.
• 2 : Error in input.

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