Commands Reference

 ls 
   -a   # list all files including hidden files
   -l   # long listing
   -t   # sort by time modified
   -R   # List all sub-directories
   -r   # list in reverse order
   -d   # to list the directory itself instead of files inside it

echo $PATH : Displays the path
/sbin/ifconfig -a : finds the IP Address
cat : look or combine
cp -r(copy all files,directories & sub-directories) -p (retains permission and owners)
cut -f <field> -d <deliminator)
date : Displays date and time
df -k, -v, -h, -m, -g : disk space
diff : Displays two files and prints the lines that are different.
du -s(usage including subdirectories) -k -h : file usage
echo : Display line of text
env : Displays unix environment variables
file : Determine file type
find -name -size -ctime -mtime -exec
grep -i -v -w .
gunzip : uncompress
gzip : compress
head : diplays ten lines of a file
hostname : systems host name
id : print user identity
kill -9 -1
last last login user -b bad login
ln -s
ls -l(long listing) -a(hidden files)
mkdir -p : make directory)
more : displays single page)
mv : move
nohup
passwd : set password
ps -e -f (list of current process)
reboot
rm : remove
rmdir : remove directory
sleep
sort -u
stty
su
tail
tee
test
tar txcrvf
touch <testfile> # creates an empty file called "testfile"
tr -s : replace repeated character with single
tty
uptime(how long its on)
uname -a(all) (print system information like kernel name,node name,os type,machine type......)
w
wall
wc -l -c -w
who Displays who is on the system.
who am i
whoami
xargs

bc
expr

at
chgrp
chmod
chown
cpio
dd
dmesg
fuser
iostat
mount
nice
netstat
renice
sar
umount
vmstat
xhost

dig
ftp
finger
host
nslookup
rcp
rlogin
rsh
telnet
traceroute
scp
ssh
sftp