Linux time Guide

⏱ Linux time Guide

Complete beginner-friendly guide to time on Linux, covering Arch Linux, CachyOS, and other distributions including command timing, performance measurement, and execution time.

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Table of Contents

1. time Basics
2. Timing Commands
3. Detailed Timing
4. Formatting
5. Troubleshooting

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⏱ time Basics

Time Command

Basic usage:

# Time command execution
time ls

# Shows execution time

Output Format

Time output:

# Output shows:
# real - wall clock time
# user - CPU time in user mode
# sys  - CPU time in kernel mode

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⏰ Timing Commands

Simple Timing

Basic timing:

# Time command
time ls

# Output:
# real    0m0.001s
# user    0m0.000s
# sys     0m0.001s

Long Running

Measure duration:

# Time long command
time sleep 5

# Shows ~5 seconds real time

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Detailed Timing

Verbose Output

More details:

# Verbose timing
/usr/bin/time -v ls

# -v = verbose (detailed statistics)

Resource Usage

Resource info:

# Resource usage
/usr/bin/time -v command

# Shows:
# - Memory usage
# - Page faults
# - Context switches
# etc.

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Formatting

Custom Format

Format string:

# Custom format
/usr/bin/time -f "%E real, %U user, %S sys" ls

# -f = format (custom format string)

Format Specifiers

Common formats:

# %E - elapsed time
# %U - user time
# %S - system time
# %M - max memory (KB)

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Troubleshooting

time Not Found

Check installation:

# time is built-in shell command
# /usr/bin/time is separate program

# Check both
which time
which /usr/bin/time

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Summary

This guide covered time usage, command timing, and performance measurement for Arch Linux, CachyOS, and other distributions.

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Next Steps

• Performance Tuning - Performance optimization
• System Monitoring - System monitoring
• htop Guide - Process monitoring
• time Documentation: man time

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