Essential Commands

A handful of text-processing commands let you slice, search, and transform data at speed. For a hacker this means filtering scan output, parsing logs, and finding secrets quickly.

This lesson covers grep, find, and awk, plus the glue between them.

grep searches text for lines matching a pattern. It is your first tool for finding interesting strings in files or output.

Search entire directory trees with -r. Combine with -n to show line numbers and -l to list only matching files.

grep -E enables extended regular expressions for flexible matching - useful for pulling IPs, emails, or tokens from messy output.

find walks the filesystem looking for files matching criteria. The most common is searching by name.

find can match by type, size, permissions, and modification time - powerful for enumeration during privilege escalation.

The -exec action runs a command on each match. The {} is replaced by the filename.

awk processes text column by column. By default it splits each line on whitespace into fields $1, $2, and so on.

Use -F to set a custom delimiter. This makes awk perfect for parsing files like /etc/passwd which use colons.

The pipe | sends one command's output into the next. Chaining grep, awk, sort, and uniq builds powerful one-liners.

Round out your toolkit:

• cut - extract columns by delimiter.
• sort / uniq - order and dedupe.
• wc -l - count lines.
• sed - stream editing and substitution.

Match the tool to the task.

You learned the core text-processing trio:

• grep finds matching lines (-r, -i, -E).
• find locates files by name, permission, time, with -exec.
• awk parses columns with custom field separators.
• Pipes chain them into powerful one-liners.

Next: managing users and processes.