I have just finished a rewarding 4 day course at OpenAdvantage on linux admin, very presented and run by Paul Cooper. I got a lot out of the course, but there was a wide range of attendees, from people with (literally) decades of unix experience to me, a microsoft convert making early steps in the command line environment. The course was based on the linuxIT course , for people working towards the linux professional institute exams (which I’m not taking!)
Overall, an excellent course. What I want to take away is a crib sheet of linux commands and notes I can sync into my address book, so that when I next need to run stuff on the command line its easy to hand. So here goes… Please note that these are my crib notes, not a definative linux command line crib sheet!
BASIC COMMAND LINE COMMANDS
echo “test” returns the text
CREDIT=300
echo $CREDIT returns the variable
ls -hl lists files in detail in human readable format
pwd tells you where you are in the directory structure
env shows the environment you are working in
ls -l >errors.txt redirects the output to errors.txt
set shows all variables
| Pipe symbol glues the lot together
ls f* gives all files starting with f
ls f???s.* gives all files but only with the right number of characters
ls [a-e]*.* for a range
ls my\ documents for files with a space in the name
SHORTCUTS
cntrol shift c and control shift v are copy and paste
tab gives tab completion of a predictable string
up arrowauto completes from the history of command lines submitted
home and end keys more up and down the line
man is the manual command for HELP!
eg
man ls
q to quit
alias ll=ls -l is a shortcut command
cd /media is absolute command to the media
FINDING FILES
find -name “f*.txt”
or
locate / “f*.txt”
REMOVE FILES
rmdir for directories
rm -r music removes the directory and all contents
COPY FILES
cp fil* my\ documents to copy
MOVE FILES
mv is move file
FILES SYSTEMS
ext2 is the linux old equivilant of fat32, a basic file format for linux
ext3 joural based file system - best to use
swap file partition should be double actual physical memory
lspci lists the hardware
RUNNING AS ROOT
sudo runs a single command as root
su is switch user eg
su - root
FORMAT DISKS
sudo fdisk /dev/sda runs the fdisk command
df tool for mounted and
du -h /usr as an example of finding file sizes
PERMISSIONS
user u
group g
other o
read r or 4
write w or 2
execute x or 1
character 1 is file info, 1-3 is user,4-6 is group,7-9 other
chmod u+x files.txt gives execute permision to users
PROCESSES
pstree -p shows the runningprocesses
ps ax shows all process for all users
kill pid number kills the process
or
kill -9 pid number
top gives the running processes
nohup runs outside the session
TEXT EDITOR
at is a basic text editor
control D stops it
head -5 hello.txt gives you the last 5 lines of hello.txt
grep term filename > results.txt
VI or VIM is a good embedded text editor
q! to quit
esc to go back to command line
x to save and escape
SSH
at command line you can ssh to any url
STOP AND START PROCESES
eg
sudo /etc/init.d/ssh stop
w
whoami tells you who is on a machine
SECURECOPY
scp root@ the address :whoteist.txt whitelist.txt is a secure copy
TIMING
crontab -l to list
crontab -e to edit
eg
45 14 * * * /bin/touch /home/demo/results.txt
will touch the results file at 14:45 every day
NETWORK
ifconfig gives you your network information, your IP address etc
I hope this is enough of a memory dump for future reference. Thanks Paul for a very useful course