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 [選項] 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:
- Open a terminal window.
- Type the
scancommand followed by the options, patterns, and file list. - 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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