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Hardware

Table of Contents

Understanding your system's hardware is crucial for performance tuning and troubleshooting. These commands reveal CPU specifications, memory configuration, disk health, and PCI device details—information essential for capacity planning and diagnosing hardware issues.

An interactive demo script is available at src/bash/hardware.sh to help you experiment with the concepts covered in this cheatsheet.

./src/bash/hardware.sh           # Run all demos
./src/bash/hardware.sh cpu       # Run CPU info demo
./src/bash/hardware.sh disk      # Run disk info demo
./src/bash/hardware.sh --help    # Show all available sections

CPU Information

Commands for viewing processor details, architecture, and performance characteristics.

Basic CPU Info

nproc                               # Number of processing units
nproc --all                         # All available processors
lscpu                               # Detailed CPU architecture info
lscpu -e                            # Extended CPU info table
lscpu -p                            # Parseable output

# macOS
sysctl -n hw.logicalcpu             # Logical CPU count
sysctl -n hw.physicalcpu            # Physical core count
sysctl -a | grep machdep.cpu        # Detailed CPU info

Detailed CPU Information

cat /proc/cpuinfo                   # Raw CPU info
cat /proc/cpuinfo | grep "model name" | head -1
cat /proc/cpuinfo | grep "cpu MHz"  # Current frequencies
cat /proc/cpuinfo | grep "cache size"

# CPU flags/features
cat /proc/cpuinfo | grep flags | head -1

# Count physical/logical CPUs
grep -c ^processor /proc/cpuinfo    # Logical CPUs
grep "physical id" /proc/cpuinfo | sort -u | wc -l  # Physical CPUs
grep "cpu cores" /proc/cpuinfo | head -1            # Cores per CPU

CPU Performance

# CPU frequency scaling
cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq
cat /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor

# CPU usage
mpstat -P ALL 1                     # Per-CPU stats (sysstat)
sar -u 1 5                          # CPU utilization over time

Memory Information

Commands for viewing RAM usage, configuration, and hardware details.

Memory Usage

free -h                             # Human-readable memory usage
free -m                             # Memory in MB
free -g                             # Memory in GB
free -s 2                           # Update every 2 seconds

# Detailed memory info
cat /proc/meminfo
cat /proc/meminfo | grep -E "MemTotal|MemFree|MemAvailable|Buffers|Cached"

# macOS
vm_stat                             # Virtual memory stats
top -l 1 | head -n 10               # Memory summary

Memory Hardware

# Physical memory details (requires root)
dmidecode -t memory                 # Memory module info
dmidecode -t memory | grep -E "Size|Type|Speed|Manufacturer"

# Memory slots
dmidecode -t memory | grep -A 16 "Memory Device" | grep -E "Size|Locator|Type:"

# Numa topology
numactl --hardware                  # NUMA node info
lsmem                               # Memory ranges

Disk and Storage

Commands for disk space, partitions, and storage device management.

Disk Space Usage

df -h                               # Disk space (human-readable)
df -h /                             # Specific mount point
df -hT                              # Include filesystem type
df -i                               # Inode usage

# Directory sizes
du -sh /path                        # Single directory size
du -sh /path/*                      # Size of subdirectories
du -sh /path/* | sort -h            # Sorted by size
du -sh /path/* | sort -rh | head -10  # Top 10 largest
du -d 1 -h /path                    # Depth-limited

# Find large files
find / -type f -size +100M -exec ls -lh {} \; 2>/dev/null
du -ah /path | sort -rh | head -20  # Largest files/dirs

Block Devices

lsblk                               # List block devices
lsblk -f                            # Include filesystem info
lsblk -o NAME,SIZE,TYPE,MOUNTPOINT,FSTYPE
lsblk -d -o NAME,SIZE,MODEL,SERIAL  # Disk details

blkid                               # Block device attributes
blkid /dev/sda1                     # Specific device

Partition Management

fdisk -l                            # List partitions (MBR)
fdisk -l /dev/sda                   # Specific disk
gdisk -l /dev/sda                   # GPT partitions
parted -l                           # All partition tables

# Partition info
cat /proc/partitions
sfdisk -l /dev/sda                  # Scriptable fdisk

Filesystem Operations

# Mount/unmount
mount /dev/sda1 /mnt                # Mount device
umount /mnt                         # Unmount
mount -o remount,rw /               # Remount with options

# Filesystem info
tune2fs -l /dev/sda1                # ext filesystem details
xfs_info /dev/sda1                  # XFS filesystem info
dumpe2fs /dev/sda1 | head -50       # ext superblock info

# Filesystem check
fsck /dev/sda1                      # Check filesystem
e2fsck -f /dev/sda1                 # Force check ext

Disk Health and Performance

# SMART monitoring
smartctl -a /dev/sda                # All SMART data
smartctl -H /dev/sda                # Health status
smartctl -t short /dev/sda          # Run short test
smartctl -l selftest /dev/sda       # Test results

# I/O statistics
iostat -x 1                         # Extended I/O stats
iostat -d -x /dev/sda 1             # Specific device
iotop                               # I/O by process

# Disk benchmark
hdparm -Tt /dev/sda                 # Read speed test
dd if=/dev/zero of=test bs=1G count=1 oflag=direct  # Write test

PCI Devices

The lspci command lists all PCI devices including network cards, GPUs, storage controllers, and other hardware components.

Basic Usage

lspci                               # List all PCI devices
lspci -v                            # Verbose output
lspci -vv                           # Very verbose
lspci -vvv                          # Maximum verbosity

lspci -k                            # Show kernel drivers
lspci -nn                           # Show numeric IDs
lspci -mm                           # Machine-readable output

Filtering Devices

# By device class
lspci | grep -i vga                 # Graphics cards
lspci | grep -i network             # Network devices
lspci | grep -i audio               # Audio devices
lspci | grep -i usb                 # USB controllers
lspci | grep -i sata                # SATA controllers
lspci | grep -i nvme                # NVMe controllers

# By vendor
lspci -d 10de:                      # NVIDIA devices (vendor 10de)
lspci -d 8086:                      # Intel devices
lspci -d 1002:                      # AMD devices

# By slot
lspci -s 00:02.0                    # Specific slot
lspci -s 00:02.0 -v                 # Detailed info for slot

Detailed Device Information

# Show device tree
lspci -t                            # Tree view
lspci -tv                           # Tree with details

# Kernel modules
lspci -k | grep -A 3 "VGA"          # GPU driver info
lspci -v -s 00:02.0 | grep "Kernel"

# Device capabilities
lspci -vvv -s 00:1f.0 | grep -i capabilities

# Update PCI database
update-pciids                       # Download latest IDs