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.