List of useful Ubuntu commands to discover information about the server.

Ubuntu Commands

Handy bash commands for finding out stuff in Linux:

# Clean up webserver permissions
find /var/www/* -type d -exec chmod 755 {} \; && find /var/www/* -type f -exec chmod 644 {} \; && chown -R www-data:www-data /var/www/*

# Add User and Add to Sudo
adduser zach
usermod -a -G sudo exampleuser

# Find CPU specifications
cat /proc/cpuinfo

# Find running kernel version
uname -r

# What compiler version do I have installed
gcc -v
gcc --version

# What is the running kernel and compiler installed
cat /proc/version

# Find X server version
X -showconfig

# What pci cards are installed and what irq/port is used
cat /proc/pci

# What kernel modules are loaded
lsmod

# Memory and swap information
cat /proc/meminfo
free
An article: Tips for Optimizing Linux Memory

# How are the hard drives partitioned
fdisk -l

# How much free/used drive space
df -h

# Show disk usage by current directory and all subdirectories
du | less

# What takes up so much space on your box
# Run from the directory in question and the largest chunk shows up last
find $1 -type d | xargs du -sm | sort -g

# What is the distribution
cat /etc/.product
cat /etc/.issue
cat /etc/issue
cat /etc/issue.net
sysinfo

# For finding or locating files
find
locate
which
whereis

# Use dmesg to view the kernel ring buffer (error messages)
dmesg | less

# Watch error messages as they happen (sysklog needed)
as root, tail -f /var/log/messages (shows last 10 lines, use a number in front of f for more lines)

# What processes are running
ps -A

# Find a process by name
ps -ef | grep -i <plain text>
For example, XCDroast
ps -ef xcdroast

# See current environment list, or pipe to file
env | more
env > environmentvariablelist.txt

# Show current userid and assigned groups
id

# See all command aliases for the current user
alias

# See rpms installed on current system
rpmquery --all | less
rpmquery --all > <filename>
rpmquery --all | grep -i <plaintext>

Autospec for tarballs
RPM tools

# What directory am I using
pwd

# Get ls colors in less
ls --color=always | less -R

Look at man <command> or info <command> for the flags I used and for other options you can use for bash commands.