unix for librarians
DESCRIPTION
WorkshopTRANSCRIPT
About me
Just a hustler making a living by pretending to know more about search than he actually does...
Workshop Goals
● Remember the roaring 90's?
● Geared towards beginners
● Lifetime guarantee!
What is Unix?
Multi-user
Multi-tasking
Hierarchical filesystem
Everything is a file
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.
Let's get started
These slides:- Slideshare
Use your own shell or
Go here:http://bellard.org/jslinux/
A brief note about shells
Many flavorsBourne (sh)Korn (ksh)Bourne-again (bash)C-shell (csh)tcsh
echo $0
How do I get in/out?
login: searchguyPassword:Authentication successful
Logout> exit, logout
id, whoami
passwd
Where am I?hostname
uname -a
pwd
cd
ls
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 dirb. are there any that begin with 'z' (just eyeball it for
now)
What's around me?
cat
less is better than more
Documentation/Locations
man
apropos
which
whereis
Exercise
1. Examine the /etc/passwd filea. what are a couple of ways of doing this?
2. Where is the "less" utility located on the filesystem?
Who's around?
who
finger
w
last
Directories
mkdir new_dir
cd dir_name
pwd
your home dir
Filescp old_file new_file
mv old_file new_file
grep search_str filename
head filename
tail filename
Exercise
1. Navigate to /etc/ directory2. Take the file named "passwd"
a. Make 4 copies in /var/tmp/b. Name them as follows:
i. passwd1, passwd2, passwd3, passwd43. Search for the string "daemon" in any one of
the 4 filesa. How many instances did you find?
Files
sort filename
uniq filename
dos2unix oldfile newfile
find path -name '*html'
wc filename
cut: selected fields from each line
File compression
gzip filename
gunzip filename.gz
zcat filename.gz
tar cvf all.tar file1 file2 file3 ...tar tvftar xvf
Hidden Files
ls -a
.profile
.cshrc
.login
.aliases
. and ..
File/Directory permissions
ls -l
-rwxr-xr-x
-u, g, o
chmod 775 filenamechmod g+w filename
Linking
ln old_file new_file
ln -s old_file new_file
Exercise: Linking
1. Navigate to /var/tmp2. Create a hardlink to the passwd3 file3. Create a symlink to the passwd4 fileWhat do you see?
1. Delete passwd3 and passwd4What do you notice?
Editing files
vi
emacs
...
What did I do?!
[and can I do it again?]
history
!!
!13
I/O Redirection, Pipes
>
<
>>
|
xargs
Exercise: I/O, Redirection
command arg1 arg2 ... > filename
● cat > io.txtUnix is great, much better than many other os'smakes me very productiveCONTROL-D
● cat < io.txt● In /var/tmp merge all passwd* files into one
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
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]
Processes
psps -ups -eps -auxww
top
Dealing with processes
kill pid
bg a process: command &
jobs
fg job_number
nice
Remotely
scp
rsync
sftp
ping
traceroute
ifconfig
Automation
at
cron
