proc
TLDR
View process information
$ cat /proc/[pid]/status
View CPU info$ cat /proc/cpuinfo
View memory info$ cat /proc/meminfo
View kernel parameters$ cat /proc/sys/kernel/hostname
SYNOPSIS
/proc filesystem documentation
DESCRIPTION
/proc is a virtual filesystem providing process and kernel information. It doesn't exist on disk - contents are generated dynamically by the kernel.
EXAMPLES
$ # CPU details
cat /proc/cpuinfo
# Memory usage
cat /proc/meminfo | grep -E "MemTotal|MemFree"
# Process command line
cat /proc/$$/cmdline
# File descriptors
ls -l /proc/$$/fd
# Environment variables
cat /proc/$$/environ | tr '\0' '\n'
# Network statistics
cat /proc/net/dev
cat /proc/cpuinfo
# Memory usage
cat /proc/meminfo | grep -E "MemTotal|MemFree"
# Process command line
cat /proc/$$/cmdline
# File descriptors
ls -l /proc/$$/fd
# Environment variables
cat /proc/$$/environ | tr '\0' '\n'
# Network statistics
cat /proc/net/dev
COMMON FILES
/proc/cpuinfo
CPU information./proc/meminfo
Memory statistics./proc/loadavg
System load averages./proc/uptime
System uptime./proc/version
Kernel version./proc/mounts
Mounted filesystems./proc/[pid]/
Per-process directory.
PER-PROCESS FILES
$ /proc/[pid]/cmdline - Command line
/proc/[pid]/cwd - Current directory
/proc/[pid]/environ - Environment
/proc/[pid]/exe - Executable link
/proc/[pid]/fd/ - File descriptors
/proc/[pid]/maps - Memory mappings
/proc/[pid]/status - Process status
/proc/[pid]/cwd - Current directory
/proc/[pid]/environ - Environment
/proc/[pid]/exe - Executable link
/proc/[pid]/fd/ - File descriptors
/proc/[pid]/maps - Memory mappings
/proc/[pid]/status - Process status
CAVEATS
Linux-specific. Some files require root. Structure varies by kernel version.
HISTORY
The /proc filesystem was introduced in Unix System V and extensively expanded in Linux for kernel introspection.
