Linux tac Guide

Complete beginner-friendly guide to tac on Linux, covering Arch Linux, CachyOS, and other distributions including reversing file output, line reversal, and reverse file display.

---

Table of Contents

1. tac Basics
2. Reversing Files
3. Separator Control
4. Multiple Files
5. Troubleshooting

---

tac Basics

Reverse File

Basic usage:

# Reverse file
tac file.txt

# Displays file in reverse order

From Input

Pipe input:

# Reverse from input
cat file.txt | tac

# Reverses piped input

---

Reversing Files

Line Reversal

Reverse lines:

# Reverse lines
tac file.txt

# Last line first, first line last

Multiple Files

Reverse multiple:

# Multiple files
tac file1.txt file2.txt

# Reverses each file

---

Separator Control

Custom Separator

Set separator:

# Custom separator
tac -s "---" file.txt

# -s = separator (splits on "---")

Regex Separator

Regex pattern:

# Regex separator
tac -r -s "^Chapter" file.txt

# -r = regex (treats separator as regex)

---

Multiple Files

Concatenate Reversed

Multiple files:

# Multiple files
tac file1.txt file2.txt

# Reverses each file separately

Combined Output

All together:

# Combined
tac file1.txt file2.txt > output.txt

# Reverses and combines

---

Troubleshooting

tac Not Found

Check installation:

# tac is part of coreutils
# Usually pre-installed

# Check tac
which tac

---

Summary

This guide covered tac usage, file reversal, and reverse file display for Arch Linux, CachyOS, and other distributions.

---

Next Steps

• cat Guide - Display files
• head Guide - View file beginnings
• tail Guide - View file endings
• tac Documentation: man tac

---

This guide covers Arch Linux, CachyOS, and other Linux distributions. For distribution-specific details, refer to your distribution's documentation.