Basic Unix Commands

1. When in doubt ..
    man commands
Samples:  man talk
   $ 
man grep
2. What’s my Unix system name, OS,CPU?
   $ uname -a
Sample result:
   SunOS hostname 5.8 Generic_108528-06 sun4u sparc SUNW, Ultra-5_10
3. Where am I (current working directory)?
   $ pwd /export/home/user
4. Who am I?
   $ who           ; returns all users who logged on to the system.
who am i ; returns only your log in name and time.

5. What is my hostname?
   $ 
hostname
6. What is my account info?
   $ finger [account]    ; to see login name, real name, TTY, idle time, when & where
7. What is my default printer?
   $ lpstat -t    ; shows printer statistic and status
8. When pressing BackSpace it shows ^H, how do I set it to work correctly?
   $ stty erasectrl-v + bs ;press ctrl-v and back space button
9. Change directory
   $ cd /usr/bin
   $ 
cd ~+                  ; ~+ = cwd or “.”   wherein ~- previous working directory
   $ 
cd $HOME         ; changes directory to your home folder = cd ~
   $ 
cd ../../hw1
cd ..                   ; moves one level up from your current working directory
10. List contents of the directory
   $ ls *[x,X]*        ; returns a listing of files that contain x or X in the file name
   $ 
ls -R               ; lists recursively that includes subdirectories 
   $ 
ls -li             ; displays long listing with inode number, or -a to list hidden files
11. File permissions
   $ chmod u+x, g-r myfileadd execute permission to user, remove read from group
   $ 
chmod u=rx, g=r, o=file   ; allows user to read and execute, group to read, no
                                                    read, write and execute for others
   $ 
chmod a=rxfile          ; allows user, group and others to read and execute
   $ 
chmod 754 myfile7-> 111 in binary represents rwx for user
                                             5-> 101 in binary represents r-x for group
                                             4-> 100 in binary represents r– for others
12. Read text file(s)
   $ 
catmyfile                    ; alternately, you can use more myfile
   $ 
catmyfile news mail    ; read multiple files
   $ 
cat *ing
13. Copy file(s)
   $ cpmyfile newfile
cp * ../hw
   $ cp -r /home/mydir /home/newdir   ; copies everything in mydir to newdir
   $ 
cp -p source destination               ; retains existing permissions (copy ACL along)
   $ 
cp -i source destination                ; does not overwrite an existing file
14. Move files to another directory
   $ mv * /home/my_account
   $ 
mvmyfile $HOME
15. Delete file(s)
   $ rm myfile
rmmyfile?        ; removes myfile1, myfile2, myfile3 and so on.
16. Make a directory
   $ mkdirmydir

17. Delete an empty directory
   $ 
rmdirmydir
18. Delete a directory that contains files and subdirectories
   $ rm-rmydir       ; removes recursively all files and subdirectories
19. Symbolic link (can span/accross file systems)
   $ ln -sfile1link1   ; uses ls -li to see link1-> file1 with 2 different inodes.
                                  symbolic link always has a=rwx permissions
20. Hard link (files contain the same inode, can not span file systems)
   $ lnfile1 link1      ; allows the same file to be accessed under different names

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