Workshop

1. Unix for Librarians
Ravi Mynampaty
searchguy@hbs.edu

2. About me
Just a hustler making a living by pretending to
know more about search than he actually
does...

3. Workshop Goals
● Remember the roaring 90's?
● Geared towards beginners
● Lifetime guarantee!

4. What is Unix?
Multi-user
Multi-tasking
Hierarchical filesystem
Everything is a file

5. Philosophy
Doug McIlroy:
● Write programs that do one thing and do it
well.
● Write programs to work together.
● Write programs to handle text streams,
because that is a universal interface.

6. Let's get started
These slides:
- Slideshare
Use your own shell
or
Go here:
http://bellard.org/jslinux/

7. A brief note about shells
Many flavors
Bourne (sh)
Korn (ksh)
Bourne-again (bash)
C-shell (csh)
tcsh
echo $0

8. How do I get in/out?
login: searchguy
Password:
Authentication successful
Logout
> exit, logout
id, whoami
passwd

9. Where am I?
hostname
uname -a
pwd
cd
ls

10. Exercise
Login to JS shell
1. Who are you logged in as?
2. What is the name of the machine?
3. What is the OS? and version?
4. What dir are you working in?
5. Change dir to /bin
a. Look at a listing of all files in that dir
b. are there any that begin with 'z' (just eyeball it for
now)

11. What's around me?
cat
less is better than more

12. Documentation/Locations
man
apropos
which
whereis

13. Exercise
1. Examine the /etc/passwd file
a. what are a couple of ways of doing this?
2. Where is the "less" utility located on the
filesystem?

14. Who's around?
who
finger
w
last

15. Directories
mkdir new_dir
cd dir_name
pwd
your home dir

16. Files
cp old_file new_file
mv old_file new_file
grep search_str filename
head filename
tail filename

17. Exercise
1. Navigate to /etc/ directory
2. Take the file named "passwd"
a. Make 4 copies in /var/tmp/
b. Name them as follows:
i. passwd1, passwd2, passwd3, passwd4
3. Search for the string "daemon" in any one of
the 4 files
a. How many instances did you find?

18. Files
sort filename
uniq filename
dos2unix oldfile newfile
find path -name '*html'
wc filename
cut: selected fields from each line

19. File compression
gzip filename
gunzip filename.gz
zcat filename.gz
tar cvf all.tar file1 file2 file3 ...
tar tvf
tar xvf

20. Hidden Files
ls -a
.profile
.cshrc
.login
.aliases
. and ..

21. File/Directory permissions
ls -l
-rwxr-xr-x
-u, g, o
chmod 775 filename
chmod g+w filename

22. Linking
ln old_file new_file
ln -s old_file new_file

23. Exercise: Linking
1. Navigate to /var/tmp
2. Create a hardlink to the passwd3 file
3. Create a symlink to the passwd4 file
What do you see?
1. Delete passwd3 and passwd4
What do you notice?

24. Editing files
vi
emacs
...

25. What did I do?!
[and can I do it again?]
history
!!
!13

26. I/O Redirection, Pipes
>
<
>>
|
xargs

27. Exercise: I/O, Redirection
command arg1 arg2 ... > filename
● cat > io.txt
Unix is great, much better than many other os's
makes me very productive
CONTROL-D
● cat < io.txt
● In /var/tmp merge all passwd* files into one

28. Exercise: Pipes
● Your merged file in /var/tmp
○ find the uniq lines
○ sort the file
○ now let's pipe it!
● sort filename | uniq
● find . -name 'pass*' | xargs grep -i nobody

29. More on pipes...
history | perl -pe 's/^ +[0-9]+//' | sort | uniq -c | sort -nr | head
"Top 200" list of directory sizes (under /dir-name - in KB)
sorted by largest:
du -dk /dir-name | sort -rn | head -200 > report.txt
List of requesting IP's from a web server log, sorted by
most frequent first:
cut -f1 -d access.log | sort | uniq -c | sort -rn
[df: free disk blocks,
du: disk usage]

30. Processes
ps
ps -u
ps -e
ps -auxww
top

31. Dealing with processes
kill pid
bg a process: command &
jobs
fg job_number
nice

32. Remotely
scp
rsync
sftp
ping
traceroute
ifconfig

33. Automation
at
cron

34. There's plenty more...
But for now...
...thanks for attending!
searchguy@hbs.edu