Introduction to UNIX
First :
Login to your Unix
account and type:
%
/home/cs476/mlist
to add your login name to cs476 mailing list.
To list all public unix/linux machines that you can login type:
%
/home/cs476/publichosts
Dot files :
To change the
behavior of programs.
Examples: .login, .cshrc,
.mailrc, .forward, etc...
You may copy /home/cs476/.cshrc to your home directory.
% cd
% cp /home/cs476/.cshrc .
Extensive on-line
documentation.
Examples: man, info, apropos, whereis,
which, etc..
Editing :
You may use any program to edit a
file.
Examples: vi, emacs.
ed, MS word, notebad, etc...
Program Management :
The programs
are available at:
/home/cs476/public_html/ProgManagement
hello : hello.o PrintDate.o
<tab> gcc -o hello hello.o PrintDate.o
hello.o : hello.c
<tab> gcc -c hello.c
PrintDate.o : PrintDate.c
<tab> gcc -c PrintDate.c
clean:
<tab> rm *.o hello
main()
{
printf("Hello
World\n");
PrintDate();
}
void PrintDate()
{
system("date");
}
% make /* produce hello */
% make clean /* removes *.o and hello */
Archive:
% tar cf hello.tar Makefile
hello.c PrintDate.c /* create */
% tar tf hello
/* list */
% tar xf hello.tar
/* extract */
% gzip
hello.tar /* compress*/
% gunzip hello.tar.gz /* uncompress */
Libraries:
The programs
are available at:
/home/cs476/public_html/ProgManagement/lib
void PrintDate()
{
system("date");
}
char *compare(int i1, int i2)
{
if
(i1 > i2) return "first";
else
if (i2 > i1) return "second";
else
return "equal";
}
int diff (int i1, int i2)
{
return
(i1-i2);
}
int sum (int i1, int i2)
{
return
(i1+i2);
}
OBJ= PrintDate.o Math.o
all: $(OBJ) libcs476.a
PrintDate.o : PrintDate.c
gcc -c PrintDate.c
Math.o : Math.c
gcc -c Math.c
libcs476.a : $(OBJ)
ar r libcs476.a $(OBJ) /* Replaces/adds files */
clean:
rm *.o libcs476.a
void PrintDate();
char *compare(int, int);
int sum(int, int);
int diff(int, int);
To list the contents of the library:
% ar t libcs476.a
/*Prints table of
contents */
Example to use the library:
The programs
are available at:
/home/cs476/public_html/ProgManagement/lib/testlib
#include <stdio.h>
#include
"../libcs476.h"
int main()
{
PrintDate();
printf("%s\n",
compare(13, 27));
printf("%d\n",
diff (13, 27));
printf("%d\n",
sum (13, 27));
}
testlibcs476 :
testlibcs476.c
gcc -o
testlibcs476 testlibcs476.c -lcs476 -L..
clean:
rm testlibcs476
-L.. search for libraries in the parent directory.
Unix file system :
% ls -l
-
rwx rwx rwx 2
wahab faculty 1278 Aug 25
file1
touch
Example:
% mkdir
test
% cd test
% touch
file
% ls -l
-rw------- 1
wahab faculty 0 Aug 1 23:25 file
In unix many commands have different
implementations and syntax.
For example:
% whereis touch
/usr/bin/touch /usr/ucb/touch /usr/local/bin/touch
% which touch
/usr/local/bin/touch
To use specific version, use the
complete path of the command.
% /usr/bin/touch
1226112272 file
% ls -l
-rw------- 1 wahab faculty 0 Dec 26 1972 file
% stat file
/*
all details about the file */
…….
Modify: 1972-12-26 11:22:00
…….
find
Example
:
Remove all files under directory test named
a.out or *.o
that have not been accessed for a week:
% find ./test \( -name a.out -o -name '*.o' \)
-atime
+7 -exec rm {} \;
Recursiveness: -R or -r
% chmod -R a+rx *
% cp -r path1
path2
% rm -r path
Creating the world's first chat!
In one window type:
% cat >> /tmp/wahab
In one
window type:
% tail -f /tmp/wahab
http://www.softlab.ntua.gr/facilities/documentation/unix/shelldiff.html
There are so many shells, for example:
% sh (Bourne shell, the oldest shell)
% bash (Bourne-again shell, a super set of sh)
% csh
(Berkeley, syntax resembles
C language)
%
tcsh (derivative
of csh)
%
ksh (korn shell-the newest
shell)
To find your default shell:
% ypcat passwd | grep wahab
wahab:stg/i.0xxJ1zU:51:13:Hussein
Abdel-Wahab:/home/wahab:/usr/local/bin/tcsh
To change your shell (if root allows) use:
All Shells has :
| >
>> < &
E.g. % ls -lt | more
Eample 1:
Producing pdf version of a man page:
% whereis
touch
touch: /usr/bin/touch
/usr/ucb/touch /usr/local/bin/touch
/usr/man/man1/touch.1 /usr/man/man1b/touch.1b
%
troff -man /usr/man/man1/touch.1 > t1
%
dpost t1 > t2
%
ps2pdf t2 touch.pdf
OR combine all the above commands
using | as:
% troff
-man /usr/man/man1/touch.1 |
dpost | ps2pdf – touch.pdf
Eample 2:
% cb < prog.c > prog.b
% more prog.b
% mv prog.b prog.c
What will happen when you
do:
% cb < prog.c > prog.c
???
We may combine all the
above commands using |
as:
% cb < prog.c | tee prog.b
You can use indent instead of cb:
%
indent prog.c
Eample 3:
% echo hi > tmp
%
tail –f tmp >> tmp &
% tail –f tmp
Job control
% tail –f tmp >> tmp
^Z
% jobs
....... list of background jobs ...........
% kill -9
%job
% ps
......... list
of processes ..................
% kill -9
process
We can also use:
% pgrep <name>
% pkill
<name>
\C
, '......' , `.......` , "....."
% echo *
%
echo \*
\ quote ONE char
%
echo ' ***><? '
' ... '
qoute ANY number of chars
% mail ` cat list ` < letter
` ... ` command substitution
% echo " ` pwd ` $home
"
"
... " does not qoute `
... `
and $
Shell & Environmnet Variables :
bourne
shell:
% sh
$ path=.:/bin:/usr/bin
path is a
standard shell variable
$ echo $path
$ d=`pwd`
d is a
user defined shell variable
$ echo $d
Note: there should be no
spaces around =
Shell variables:
has to be explicitly exported to be accessed
by child process.
Example:
$ d=`pwd`
$ export d
$ sh
$ echo $d
csh
shell:
$ csh
% set path = .:/bin:/usr/bin
% set
d = `pwd`
% echo
$d
% setenv DISPLAY
vega.cs.odu.edu:0
% echo $DISPLAY
Environment
variables: are automatically
exported to all child processes.
Example: