Informacion del sistema operativo OS

Distribution

cat /etc/issue
cat /etc/*-release
cat /etc/lsb-release      # Debian based
cat /etc/redhat-release   # Redhat based

Kernel

cat /proc/version
uname -a
uname -mrs
rpm -q kernel
dmesg | grep Linux
ls /boot | grep vmlinuz-

Environment

cat /etc/profile
cat /etc/bashrc
cat ~/.bash_profile
cat ~/.bashrc
cat ~/.bash_logout
env
set

Printers

lpstat -a

Sys calls

cat /usr/include/i386-linux-gnu/asm/unistd_32.h

Kernel tuning

Temporary:

sysctl

Permanent:

/etc/sysctl.conf

View configuration:

sysctl -a |less

View configuration files for the installed modprobe modules:

ls -l /etc/modprobe.d/
ls -R /lib/modules/$( uname -r )/kernel

Kernel Modules

Insert module:

insmod

Remove module:

modprobe -r
rmmod

List modules:

modprobe -l
lsmod

Installed Applications / Versions

ls -alh /usr/bin/
ls -alh /sbin/
dpkg -l
rpm -qa
ls -alh /var/cache/apt/archivesO
ls -alh /var/cache/yum/

Scheduled Jobs

crontab -l
ls -alh /var/spool/cron
ls -al /etc/ | grep cron
ls -al /etc/cron*
cat /etc/cron*
cat /etc/at.allow
cat /etc/at.deny
cat /etc/cron.allow
cat /etc/cron.deny
cat /etc/crontab
cat /etc/anacrontab
cat /var/spool/cron/crontabs/root