# Cheat Sheet #day53 - less

# `less` Command Cheatsheet

The `less` command in Unix/Linux is a terminal pager program used to view (but not modify) the contents of a file one screen at a time. It allows for both forward and backward navigation through the file.

## Basic Syntax

```bash
less [OPTIONS] [FILE]
```

## Navigation Commands

* `Space` or `f`: Move forward one screen.
    
* `b`: Move backward one screen.
    
* `Enter`: Move forward one line.
    
* `y`: Move backward one line.
    
* `d`: Move forward half a screen.
    
* `u`: Move backward half a screen.
    
* `g`: Go to the beginning of the file.
    
* `G`: Go to the end of the file.
    
* `ng`: Go to line number `n`.
    
* `/pattern`: Search forward for `pattern`.
    
* `?pattern`: Search backward for `pattern`.
    
* `n`: Repeat previous search (forward).
    
* `N`: Repeat previous search (backward).
    

## Options

* `-N`: Display line numbers.
    
* `-S`: Chop long lines (don't wrap).
    
* `-X`: Disable termcap initialization/deinitialization (useful in scripts).
    
* `-F`: Automatically exit if the file fits on one screen.
    
* `-R`: Display raw control characters.
    
* `-i`: Ignore case in searches.
    
* `-m`: Display a more verbose prompt.
    

## Useful Commands

* `h`: Display help screen.
    
* `q`: Quit `less`.
    
* `&pattern`: Display only lines matching the pattern.
    
* `m<letter>`: Mark the current position with `<letter>`.
    
* `'letter`: Return to a previously marked position.
    
* `=`, `Ctrl+g`: Display the current file name, line number, and percentage through the file.
    
* `F`: Follow the end of the file as it grows (like `tail -f`).
    

## Examples and Use Cases

### View a File

```bash
less filename.txt
```

* Opens `filename.txt` for viewing.
    

### View with Line Numbers

```bash
less -N filename.txt
```

* Opens `filename.txt` with line numbers displayed.
    

### Search for a Pattern

```bash
less filename.txt
```

* Inside `less`, type `/pattern` and press `Enter` to search for `pattern`.
    

### Ignore Case in Searches

```bash
less -i filename.txt
```

* Opens `filename.txt` and ignores case in searches.
    

### Follow File Growth

```bash
less +F filename.txt
```

* Opens `filename.txt` and follows the end of the file as it grows.
    

### Display Long Lines Without Wrapping

```bash
less -S filename.txt
```

* Opens `filename.txt` and does not wrap long lines.
    

### View Command Output

```bash
command | less
```

* Pipes the output of `command` to `less` for easier viewing.
    

### View Multiple Files

```bash
less file1.txt file2.txt
```

* Opens `file1.txt`, and after quitting, `file2.txt` will be opened.
    

### Jump to a Line Number

```bash
less filename.txt
```

* Inside `less`, type `50g` to jump to line 50.
    

---

This cheatsheet provides a quick reference to the most common usages and options for the `less` command. For more detailed information, you can always refer to the `less` man page by typing `man less` in your terminal.