Identification ¶

Users

• w: who is logged in, and what they are doing
• who: who is logged in
• whoami: username
• last: list of last logged users
• id: username, group...
• groups: list groups
• /etc/groups: see members for each group
• finger: return a summary of information about a user

Machine

• echo $0: language used by the current shell
• uname -a: info about the kernel
• hostname: info about the host (ex: website-dev -> role of the user)
• /proc/version: information about the machine kernel
• /etc/*release: information about the operating system
• /etc/issue: an alternative to find the OS/version
• ps -e / top: see running processes, first column==owner
• env: see environment variables
• lscpu: list information about the CPU

Permissions

• umask: see the default perms on newly created files
• find / -writable -type d 2>/dev/null: find writable directories
• /etc/passwd: usernames, their groups, their home, and their shell
• /etc/shadow (root): username, and their hashed password
• /etc/sudoers (root): sudoers, and rules applied to them, if any

Services

• Apache: apache2 -v / apache2ctl -M
• Sudo: sudo -V
• PostgresSQL: psql -V
• MySQL: mysql --version
• Port and services: /etc/services
• Apps: dpkg -l

Network

• Ports: netstat -antp | grep -i list
• DHCP (DNS...): /var/lib/dhcp/dhcpd.leases
• DNS: /etc/resolv.conf, /etc/hosts