Print working directory, i.e., display the name of my current directory on the screen.
• hostname
Print the name of the local host (the machine on which
you are working). Use netconf (as root) to change the name of the machine.
• whoami
Print my login name.
• id username
Print user id (uid) and his/her group id (gid), effective
id (if different than the real id) and the supplementary groups.
• date
Print or change the operating system date and time. E.g.,
I could change the date and time to 2000-12-31 23:57 using this command:
date 123123572000
To set the hardware (BIOS) clock from the system (Linux)
clock, use the command (as root) setclock
• time
Determine the amount of time that it takes for a process
to complete + other info. Don't confuse it with the date command. E.g.
I can find out how long it takes to display a directory content using:
time ls
• who
Determine the users logged on the machine.
• rwho -a
(=remote who) Determine all users logged on your network.
The rwho service must be enabled for this command to run. If it isn't,
run setup as root to enable "rwho".
• finger user_name
System info about a user. Try: finger root
• last
Show listing of users last logged-in on your system.
• history | more
Show the last (1000 or so) commands executed from the
command line on the current account. The "| more" causes the display to
stop after each screenful.
• uptime
Show the amount of time since the last reboot.
• ps
(=print status) List the processes currently run by the
current user.
• ps axu | more
List all the processes currently running, even those
without the controlling terminal, together with the name of the user that
owns each process.
• top
Keep listing the currently running processes, sorted
by cpu usage (top users first). In KDE, you can get GUI-based Ktop from
"K"menu under "System"-"Task Manager" (or by executing "ktop" in an X-terminal).
• uname -a
(= Unix name with option "all") Info on your (local)
server. I can also use guname (in X-window terminal) to display the info
more nicely.
• free
Memory info (in kilobytes).
• df -h
(=disk free) Print disk info about all the filesystems
(in human-readable form)
• du / -bh | more
(=disk usage) Print detailed disk usage for each subdirectory
starting at the "/" (root) directory (in human legible form).
• cat /proc/cpuinfo
Cpu info--it show the content of the file cpuinfo. Note
that the files in the /proc directory are not real files--they are hooks
to look at information available to the kernel.
• cat /proc/interrupts
List the interrupts in use.
• cat /proc/version
Linux version and other info
• cat /proc/filesystems
Show the types of filesystems currently in use.
• cat /etc/printcap
Show the setup of printers.
• lsmod
(As root. Use /sbin/lsmod to execute this command when
you are a non-root user.) Show the kernel modules currently loaded.
• set|more
Show the current user environment.
• echo $PATH
Show the content of the environment variable "PATH".
This command can be used to show other environment variables as well. Use
"set" to see the full environment.
• dmesg | less
Print kernel messages (the content of the so-called kernel
ring buffer). Press "q" to quit "less". Use less /var/log/dmesg to
see what "dmesg" dumped into this file right after the last system bootup.
