You'll need this to start:
Login and password
Exit or Ctrl+ D to log out
# backspace
@ deleted the entire line
$ this is the prompt for the Borne Shell, or korn, or POSIX,
most commands are in /usr/bin/(shell)
# means you're logged in as root.
white space (space or tab) seperates commands from arguments.
Single commands are seperated by a ; Like ls;pwd or a pipe.
Cntl + c terminates a command
My Current releasae is Centos Linux release 7.9.2009
uname -a and
lsb_release -a both return the version.
uname - a shows the following in order:
Kernal Name, Network node hostname, Kernal release date, versionmachin name and os.
Man -k for keyword man
in the Manual:
space - advances by a line,
return - advances by a page,
q - quits the Man.
Commands:
whereis
id
who
date
passwd
echo
clear
write
mesg
news
/etc/passwd this is where the user info is stored
/etc/group this is where the group info is stored
Module 4
Relative and Absolute paths
use the forward slash /
. representd the current dir
.. represents the dir above, or the parent dir..
So if I'm in my home dir, /home/Jay, then when I type this .. I'm moved to /home.
typing cd brings me back to /home/Jay
pwd - present working dir.. Tells you where you are.
ls - use ls -alis | more
cd remember without an argument this always brings you home
find
mkdir
rmdir
Commands from Chapter 5.
Remember to ue the -i option (check it) to set the warning for overwrite for mv, cp and maybe a few others..
And in .profile or in Centos .bashrc set noclobber
cat (use cat -n to show line numbers, and you can viw multipe files)
more (you can view multiple files)
less - has more options to view file like with vi commands
tail
cp
mv - remember you need w permisn in the source and destination if you are mving a file to a new folder
ln
rm
lp lpr
lpstat
cancel
Also remember - an easy way to crete a file is cat > [File]
Commands from Chapter 6.
touch (updates or creates a file)
chmod (set to remove "w" permission for group and other to avoid losing the file
umask (set it in the .profile)
chown
su Switch User - you will need the other user's pw.
A few hints to remember..
cd - brings you home
tty - tells you the file of the terminal you're on
ps - shows processes running, so use ps -ef or try ps -ef | grep (ther tty you're on)
set aliases n the profile after proving them, so try dir='ls -alsi | more'\
and
Cat commands:
Cat to view: To view contents.. ex: “Cat poems” displays the contents of the file poems on screen.
Cat displays multiple files at the same time.. ex: # cat file1.txt file2.txt file3.txt
Cat with redirect: The command can also be used to concatenate (join) multiple files into one single file using the “>” Linux redirection operator. Ex: # cat file1.txt file2.txt file3.txt > file-all.txt
Cat with Append redirect: “cat file1 >> fileall” puts the contents of file1 at the end of fileall.
User redirect to copy a file to a new file name or directory.
Create a file with redirect: “Cat > fish” ent. Ctl+d to stop entering text.
Number the lines of output: ex: “cat -n fish”, “cash -b fish”
Use with | more to page through screens.
cat /proc/cpuinfo
cat Weekdays.txt | hexdump -C
cat Weekdays.txt | xxd -b