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wc

text processingLinux/Unix

The wc command is one of the most frequently used commands in Linux/Unix-like operating systems. wc Print newline, word, and byte counts for files

See Examples View Syntax

Quick Reference

Command Name:

wc

Category:

text processing

Platform:

Linux/Unix

Basic Usage:

wc [options] [arguments]

Common Use Cases

Syntax

wc [OPTION]... [FILE]...

Options

Option	Description
`-c, --bytes`	Print the byte counts
`-m, --chars`	Print the character counts
`-l, --lines`	Print the newline counts
`-L, --max-line-length`	Print the length of the longest line
`-w, --words`	Print the word counts
`--help`	Display help information and exit
`--version`	Output version information and exit

Output Format

By default, wc displays four columns of information in this order:

Column	Information
1	Number of lines
2	Number of words
3	Number of bytes
4	Filename (if provided)

When multiple files are provided, wc displays the counts for each file and a total line at the end.

Examples

How to Use These Examples

The examples below show common ways to use the wc command. Try them in your terminal to see the results. You can copy any example by clicking on the code block.

# Basic Examples Basic

# Count lines, words, and bytes in a file wc file.txt

# Count only lines in a file wc -l file.txt

# Count only words in a file wc -w file.txt

# Count only bytes in a file wc -c file.txt

# Count only characters in a file wc -m file.txt

# Advanced Examples Advanced # Count lines in multiple files wc -l file1.txt file2.txt file3.txt # Count lines from standard input

cat file.txt | wc -l

# Count lines in all text files in current directory wc -l *.txt # Get the longest line length wc -L file.txt # Display all counts with no filename wc -lwm file.txt # Count total number of files in a directory ls | wc -l # Count unique words in a file

cat file.txt | tr ' ' '\n' | sort | uniq | wc -l

# Count non-empty lines grep -v "^$" file.txt | wc -l

Try It Yourself

Practice makes perfect! The best way to learn is by trying these examples on your own system with real files.

Understanding Syntax

Pay attention to the syntax coloring: commands, options, and file paths are highlighted differently.

Notes

The `wc` (word count) command is a simple yet versatile utility for counting lines, words, characters, and bytes in text files. It's one of the core text processing tools in Unix-like operating systems and is frequently used in shell scripts and command pipelines. **Core Functionality:** 1. **Counting Elements**: wc's primary purpose is to count various elements in text files: - Lines (newline-terminated sequences) - Words (sequences of non-whitespace characters) - Bytes (total size of the file) - Characters (may differ from bytes in multi-byte encodings like UTF-8) - Maximum line length (the longest line in a file) 2. **Multiple File Support**: wc can process multiple files at once, displaying statistics for each file and a total summary. 3. **Standard Input**: When no file is specified, wc reads from standard input, making it useful in command pipelines. **Common Use Cases:** 1. **File Statistics**: Quickly determine the size and composition of text files. 2. **Line Counting**: Count the number of lines in logs, code files, or data sets. ``` wc -l logfile.txt ``` 3. **Word Counting**: Count words in documents for writing projects or analysis. ``` wc -w essay.txt ``` 4. **Directory Content Analysis**: Count files or specific types of content. ``` ls | wc -l # Count files in directory grep -c "error" log.txt # Count error occurrences ``` 5. **Data Processing**: Use wc in pipelines to analyze output from other commands. ``` ps aux | wc -l # Count running processes ``` **Technical Details:** 1. **Word Definition**: wc considers a word to be a sequence of characters delimited by whitespace. This means that punctuation attached to words is counted as part of the word. 2. **Line Counting**: wc counts newline characters (\n), so an empty line is counted as a line, but the last line without a newline character might not be counted depending on the implementation. 3. **Character vs. Byte Counting**: In ASCII files, character count (-m) and byte count (-c) will be identical. In files with multi-byte characters (like UTF-8), they may differ. 4. **Performance**: wc is highly optimized and can process large files efficiently, making it suitable for use with substantial data sets. **Common Patterns and Combinations:** 1. **Finding Non-Empty Lines**: ``` grep -v "^$" file.txt | wc -l ``` 2. **Counting Unique Words**: ``` cat file.txt | tr ' ' '\n' | sort | uniq | wc -l ``` 3. **Finding Lines with Specific Content**: ``` grep "pattern" file.txt | wc -l ``` 4. **Comparing File Sizes**: ``` wc -c file1.txt file2.txt ``` **Historical Context:** The wc command has been part of Unix since its early days and is included in the POSIX standard. Its simplicity and utility have made it a staple tool for text processing across decades of computing history. While there are more specialized tools for complex text analysis, wc remains valuable for its speed, reliability, and universal availability across Unix-like systems. **Implementation Variations:** Different Unix implementations may have slight variations in wc behavior: 1. GNU wc (common on Linux) offers additional options like --max-line-length (-L). 2. BSD wc (found on macOS) may have slightly different output formatting. 3. Some versions count the final line even without a newline terminator, while others require the newline. Despite these minor differences, the core functionality remains consistent across platforms, making wc a reliable tool in cross-platform scripts and workflows.

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Use Cases

Learn By Doing

The best way to learn Linux commands is by practicing. Try out these examples in your terminal to build muscle memory and understand how the wc command works in different scenarios.

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$ wc

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