# Searching using CLI

## Useful commnads

* GREP searches any given input files, selecting lines that match one or more patterns.
* CUT cuts out selected portions of each line from each file and writes them to the standard output.
* SED reads the specified files, modifying the input as specified by a list of commands.
* AWK scans each input file for lines that match any of a set of patterns.
* SORT sorts text and binary files by lines.
* UNIQ reads the specified input file comparing adjacent lines and writes a copy of each unique input line to the output file.

## Examples

* Example 1
  * `216.67.1.91 - leon [01/Jul/2002:12:11:52 +0000] "GET /index.html HTTP/1.1" 200 431`
  * command `grep '/api/payments' access.log | cut -d ' ' -f 1 | sort | uniq -c | sort -rn | head -10`
  * grep '/api/payments' access.log: This filters the lines containing "/api/payments" from the access.log file
  * cut -d ' ' -f 1: This extracts the first field (the IP address) from each line. The -d ' ' option specifies space as the field delimiter.
  * uniq -c: This removes duplicate lines and prefixes lines by the number of occurrences.
  * sort -rn: This sorts the lines in reverse order (highest first) numerically.
  * head -10: This shows only the first 10 lines of the output, which correspond to the top 10 IP addresses.


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# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://hanfak.gitbook.io/workspace/operating-system/bash-searching.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.