1.5 KiB
1.5 KiB
📘 Using grep in Linux/Unix
grep (Global Regular Expression Print) is a powerful command-line utility used to search for text patterns in files. Below are common variations of the grep command with examples and explanations.
🔍 Basic Search
grep "hello" file1
Description:
Searches for lines containing the word hello in file1. The search is case-sensitive.
🔍 Case-Insensitive Search
grep -i "hello" file1
Description:
Performs a case-insensitive search for hello in file1. Matches hello, Hello, HELLO, etc.
🔢 Show Line Numbers
grep -n "hello" file1
Description: Displays matching lines with their line numbers.
🔢 Case-Insensitive with Line Numbers
grep -in "hello" file1
Description:
Combines -i and -n to show line numbers and ignore case.
🚫 Invert Match
grep -v "hello" file1
Description:
Shows lines that do NOT contain the word hello.
🚫 Invert, Ignore Case, and Show Line Numbers
grep -ivn "hello" file1
Description: Combines all the above:
-i: Ignore case-v: Invert match-n: Show line numbers Shows all lines that don’t containhello, regardless of case, and includes line numbers.
✅ Summary of Flags
| Flag | Description |
|---|---|
-i |
Ignore case |
-n |
Show line numbers |
-v |
Invert the match (exclude) |