Informational
crontab –l
to list the system conjobs

cat [opts] [filepattern] •Print file contents on STOUT
-E :Display a $ at the end of each line.
-T :Show tabs as ^I.
-v :Show non-printing characters.

date [opts] •Print or set the system date and time
--date=STRING :display time described by STRING.
--set=STRING :set time described by STRING.

dmesg [opts] •Print or control the kernel ring buffer
-c :Clear the contents of the ring buffer.

file [opts] [filepattern] •Determine the file type
-z :Try to look inside compressed files.

finger [opts] [userpattern] •Show info about system users
-m :Match the exact username specified.

free [opts] •Display free and used memory in the system
-b :Display the information in bytes.

hexdump [opts] •Show all the characters of a file
-c :Display the input offset in hexidecimal

last [opts] [username] •Show last system logins for users
-num :Show last num of sessions.
-a :Display the hostname in the last column.
-d :Translates IP numbers to their hostname.
-f :Use file as last log.

less [opts] [filepattern] •View a file a page at a time
-i :Do case insensitive searching.
-S :Don’t wrap long lines.

man [opts] [section] •View online manual pages.
-a :View all available manual pages for name.
-k string :Search for the specified string.

md5sum [opts] [filepattern] •Show the uniqueness of files

ps [opts] •Show what processes are running on the system
a :Select all processes on a terminal.
u :Display user oriented format. More columns.
x :Select processes without a controlling TTY.
w :Show an extra line of process entry per w.
Ex: ps auxwww =Displays all process information on system.

quota [opts] [user] •Display disk usage and limits
-v :Display filesystems where no quota is set.

time [opts] [command] •Show resource usage for a command

top [opts] •Display top CPU processes every X seconds
-d sec :Set the delay to sec seconds before refreshing.

umask [opts] [mode] •Set the default file permissions
-S :Show current symbolic umask.

uname [opts] • Show OS and system information
-a :Show everything

uptime • Show system uptime and load

w [opts] [user] • Show who is logged in/what they are doing
whereis [command] • Locate the related files for a command
which [command] • Show full path to the specified command
who [opts] [args] • Show who is logged in
• Check your ps output and see what it is running:
ps axf

Harware info stuff :

Information regarding partitions :
just use shell and type df which will give you the allocated space for all your partitions !

cat /proc/cpuinfo ----List info about CPU.

and additional info!
/sbin/lspci ---- list all PCI devices (result of probe) Also lspci -vvx and cat /proc/pci
cat /proc/interrupts ----List IRQ's used by system.
cat /proc/ioports ----List I/O ports used by system.
cat /proc/dma ----List DMA channels and device used by system.

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