Script languages

NB.: This section will be updated frequently

Introduction: The script languages that have interpreters operating under Linux OS (we shall be concerned here with simplyMEPIS VERSION 6.5) and will be coverd, here, in this section are: perl, python, tcl, tk, ruby, rexx (regina) and haskell. In order to prepare scripts in different languages and have them run in the terminal (konsole) window, it is suggested to first set up the appropriate icons and folders on the desktop as follows:

Right click the mouse (i.e. click the right btton on your mouse), then choose Create new and then click folder from the subcontext menu that will appear on the screen.
Enter the folder name, example My scripts. Double-click the folder you have just created and start adding the links to applications.
Right-click your mouse, then choose Create new and click Link to application. In the dialogue box that will appear (under the general tab), type the name of the script language, eg. my perl scripts. Click the Application tab, then go to the Work path field, click on the icon to the left of the field then click on the folder having you scripts (in our example would be perl scripts). Then go to the command field and type konsole, then click the OK button in the dialogue (tab) box.
Now you have an icon in the scripts file (on your desktop) for perl ones, you can have additional ones for python, tcl, ruby,...etc.
When you click this icon a shell session will start in the scripts directory that you want, eg. perl. You can get a list of files in the directory (by typing dir or ls at the prompt), then you can start your perl scripts by typing perl followed by a space and the file name (having the script) with .pl extension. If you have the sha-bang in your script (this special first line is #!/usr/bin/perl), then you run your script with ./ and the file name with its extension (with no space between ./ and the file name). The same applies to the other scripting languages mentioned here.

Script language	Running the script	Interpreter version
perl	perl (or ./) hellop.pl	v. 5.8.7
python	python (or ./) hellopython.py	v. 2.4.3
tcl	tclsh (or ./) hellotcl.tcl	8.3 & 8.4
ruby	ruby (or ./) hellor.rb	v. 1.8.4
rexx	rexx (./) hellor.rexx	regina v.3.3.5.00
tk	wish hellotk.tcl	v. 8.3 & 8.4
haskell	hugs or ghci then the filename with .hs extension. Evaluate the expression (or function) by typing its name, eg. hugs (or ghci) hellointer.hs, hit enter and type hellointer (to evaluate the expression or function)	hugs v. 20050308 or ghci v. 6.4.1

Saying hello in different scripting languages:
Perl:

Open a new document in any text editor (kwrite, kedit or kate).
Type the following lines:
#!/usr/bin/perl
print "Hello from ActivePerl!";
Save the file as hellop.pl
Run the script by typing ./hellop.pl

Python:

Open a new document in any text editor (kwrite, kedit or kate).
Type the following lines:
#!/usr/bin/python
print "Hello from the Python"
Save the file as hellopython.py
Run the script by typing ./hellopython.py

tcl:

Open a new document in any text editor (kwrite, kedit or kate).
Type the following lines:
#!/usr/bin/tclsh
puts stdout {Hello from TCL/TK};
Save the file as hellotcl.tcl
Run the script by typing ./hellotcl.tcl

Ruby:

Open a new document in any text editor (kwrite, kedit or kate).
Type the following lines:
#!/usr/bin/ruby
print "Hello World\n"
Save the file as hellor.rb
Run the script by typing ./hellor.rb

Rexx:

Open a new document in any text editor (kwrite, kedit or kate).
Type the following lines:
#!/usr/bin/rexx
say "Hello world from REXXX"
Save the file as hellor.rexx
Run the script by typing ./hellor.rexx

tk:

Open a new document in any text editor (kwrite, kedit or kate).
Type the following lines:
#!/usr/bin/wish
#exec wish "$0" $@"
button .hello -text "Hello from Tk" -command {
puts stdout "Hello from Tk"; destroy .
}
pack .hello
Save the file as hellotk.tcl
Run the script by typing ./hellotk.tcl

A simple mathematical program (accepting user input, making simple calculatins and outputing results to screen):
Perl:

Open a new document in any text editor (kwrite, kedit or kate).
Type the following lines:
#!/usr/bin/perl
print ("enter first number: \n");
$noe=;
print ("enter second number: \n");
$el2=;
$req=($noe)+($el2);
$req1=($noe)*($el2);
$req2=($noe)/($el2);
$req3=($noe)-($el2);
print ("the sum of the 2 numbers = $req\n");
print ("the multiplication of the 2 numbers = $req1\n");
print ("the division of the first number by the second = $req2\n");
print ("the first number minus the second = $req3\n");
format printtosc =
********************************************************************************
The Result
sum of the numbers =@>>>>.the multiplication of the numbers =@>>>>,the division of the first number by the second =@>>>>, the first number minus the second =@>>>>
$req,$req1,$req2,$req3
********************************************************************************
.
$~="printtosc";
write(STDOUT);
Save the file as simpleperl.pl
Run the script by typing ./simpleperl.pl

Python:

Open a new document in any text editor (kwrite, kedit or kate).

Save the file as simplepython.py
Run the script by typing ./simplepython.py

tcl:

Open a new document in any text editor (kwrite, kedit or kate).
Type the following lines:
#!/usr/bin/tclsh
proc deltawye {} {
puts "Enter the value of the first number eg. 3.0: "
set el2 [gets stdin]
puts "Enter the second number per above indicated format: "
set el1 [gets stdin]
set result0 [expr ($el2+$el1)]
set result1 [expr ($el1*$el2)]
set result2 [expr ($el2-$el1)]
set result3 [expr ($el2/$el1)]
puts "the sum of 2 numbers = $result0"
puts "the multiplication of 2 numbers = $result1"
puts "the second number minus the first = $result2"
puts "dividing the first numbe by the second = $result3"
}

set choice ""
while {$choice != "q"} {
puts "Enter c to proceed & q to exit: "
set choice [gets stdin]
if {$choice == "c"} {deltawye}
if {$choice == "q"} {exit}
}
Save the file as simpletcl.tcl
Run the script by typing ./simpletcl.tcl

Ruby:

Open a new document in any text editor (kwrite, kedit or kate).
Type the following lines:
#!/usr/bin/ruby
print "enter a number\n"
a = STDIN.gets.chomp.to_f
print "enter another number\n"
b = STDIN.gets.chomp.to_f
c = a+b
d = a-b
e = a*b
f = a/b
print "sum = ",c,"\n"
print "second number minus the first = ",d,"\n"
print "multiplication = ",e,"\n"
print "first number divided by the second = ",f,"\n"
Save the file as simpleruby..rb
Run the script by typing ./simpleruby.rb

Rexx:

Open a new document in any text editor (kwrite, kedit or kate).
Type the following lines:
#!/usr/bin/rexx
say "enter a number"
pull a
say "enter another number"
pull b
c = a+b
d = a-b
e = a*b
f = a/b
say "sum = " c
say "second number minus the first = " d
say "multiplication = " e
say "first number divided by the second = " f
Save the file as simplerrexx.rexx
Run the script by typing ./simplerrexx.rexx

Finding the area of a square, a rectangle or a circle:
Perl:

Open a new document in any text editor (kwrite, kedit or kate).

Type the following lines:

   #!/usr/bin/perl
while ($q==0){
print "enter 1 for area of a square,\n2 for area of a rectangle,\n3 for area of a circle and 4 to quit: \n\n";
$choice=;
print("\n");
if($choice == 1) {
print ("enter base length of square: \n");
$noe=;
$req=$noe*$noe;
print ("the area = $req\n");

format printtosc =
********************************************************************************
                               The Result
area =@>>>>
$req
********************************************************************************
.
$~="printtosc";
write(STDOUT);
print ("to save result to data file, enter 1: ");
$fchoice=;
if ($fchoice==1) {
print ("to append file enter 1 & to ovewrite/create, enter 2: ");
$appover=;
if ($appover==1){
format printtofile =
==================================================================================
area =@>>>>
$req
==================================================================================
.
print ("enter file name: ");
$filenam=;
open(myfile,">>$filenam");
select(myfile);
$~="printtofile";
write(myfile);
close(myfile);
select(STDOUT);
}
elsif ($appover==2){
print ("enter file name: ");
$filenam=;
open(myfile,">$filenam");
select(myfile);
print ("the equivalent = $req\n");
print("the $noe elements are: $el1, $el2 & $ el3");
close(myfile);
select(STDOUT);
}
}
}
elsif($choice == 2) {
print ("enter base length of rectangle: \n");
$noe=;
print ("enter height of rectangle: \n");
$noe1=;
$req=$noe*$noe1;
print ("the area = $req\n");
}
elsif($choice == 3) {
print ("enter radius of circle: \n");
$noe=;
$req=$noe*$noe*3.14159;
print ("the area = $req\n");
}
elsif($choice == 4) {last;}
}

Save the file as areasperl.pl
Run the script by typing ./areasperl.pl

Python:

Open a new document in any text editor (kwrite, kedit or kate).

Type the following lines:

  
#!/usr/bin/python
print "areas"
choice =""
while choice != "q":
	print "enter choice: a for a square area, b a rectangle, c for a circle area and q to quit"
	choice = raw_input()
	if choice == "a":
		print "a square area"
		print "base length of square"
		base = float(raw_input())
		area=(base*base)
   		print "the area of square = ",area
    		print "overwrite enter o, append enter a"
    		appover = raw_input()
    		if appover == "o":
        		print "enter file name"
        		fnam = raw_input()
        		f=open(fnam, 'w')
        		f.write ('\nthis is to overwrite or create\n')
        		f.write (area)
        		f.close()
    		if appover == "a":
        		print "enter file name"
        		fnam = raw_input()
        		f=open(fnam, 'a')
        		f.write ('\nthis is to append\n')
        		f.write (area)
        		f.close()
				
	if choice == "b":
		print "rectangle area"
                print "base length of rectangle"
		base = float(raw_input())
                print "height of rectangle"
		height = float(raw_input())
		area=(height*base)
   		print "the area of rectangle = ",area
    	if choice == "q":
		break

Save the file as areaspy.py
Run the script by typing ./areaspy.py

tcl:

Open a new document in any text editor (kwrite, kedit or kate).

Type the following lines:

  
#!/usr/bin/tclsh
proc square {} {
puts "base length of square eg 2.0: "
set el1 [gets stdin]
set res [expr ($el1*$el1)]
puts "the area = $res"
puts "to save to data file: to overwrite enter 1; to append enter 2 (press enter key to skip)"
set overappe [gets stdin]
if {$overappe == 1} {
puts "overwrite, enter filename to create/overwrite"
set filenam [gets stdin]
set fileid [open $filenam w]
puts $fileid "the base length & area are: $el1, $res"
close $fileid
}
if {$overappe == 2} {
puts "append, enter filename to append"
set filenam [gets stdin]
set fileid [open $filenam a]
puts $fileid "the base length & area are: $el1, $res"
close $fileid
}
}
proc circle {} {
puts "radius of circle eg 2.0: "
set el1 [gets stdin]
set res [expr ($el1*$el1*3.14159)]
puts "the area = $res"
puts "to save to data file: to overwrite enter 1; to append enter 2 (press enter key to skip)"
set overappe [gets stdin]
if {$overappe == 1} {
puts "overwrite, enter filename to create/overwrite"
set filenam [gets stdin]
set fileid [open $filenam w]
puts $fileid "the radius and area are: $el1, $res"
close $fileid
}
if {$overappe == 2} {
puts "append, enter filename to append"
set filenam [gets stdin]
set fileid [open $filenam a]
puts $fileid "the radius and area are: $el1, $res"
close $fileid
}
}

proc rectangle {} {
puts "base length of rectangle according to following format nn.nn eg. 3.0: "
set el2 [gets stdin]
puts "height of rectangle per above indicated format: "
set el1 [gets stdin]
set result0 [expr ($el2*$el1)]
puts "the area = $result0"
puts "to save to data file: to overwrite enter 1; to append enter 2 (press enter key to skip)"
set overappe [gets stdin]
if {$overappe == 1} {
puts "overwrite, enter filename to create/overwrite"
set filenam [gets stdin]
set fileid [open $filenam w]
puts $fileid "the height, base length and area are: $el1, $el2, $result0"
close $fileid
}
if {$overappe == 2} {
puts "append, enter filename to append"
set filenam [gets stdin]
set fileid [open $filenam a]
puts $fileid "the height, base length and area are: $el1, $el2, $result0"
close $fileid
}
}

set choice ""
while {$choice != "q"} {
puts -nonewline "Enter a for area of a square, \nb for area of rectangle, \nc for area of circle & q to exit: "
set choice [gets stdin]
if {$choice == "a"} {square}
if {$choice == "b"} {rectangle}
if {$choice == "c"} {circle}
if {$choice == "q"} {
exit}
}

Save the file as areastcl.tcl
Run the script by typing ./areastcl.tcl

Ruby:

Open a new document in any text editor (kwrite, kedit or kate).

Type the following lines:

#!/usr/bin/ruby
quit = 0
while quit == 0
print "enter 1 for area of a square, 2 for area of rectangle, 3 for area of circle and 4 to quit\n"
choice = STDIN.gets.chomp.to_i
if choice == 1 then
print "area of a square\n"
print "enter base length of square\n"
a = STDIN.gets.chomp.to_f
c = a*a
print "area of square = ",c,"\n"
elsif choice == 2 then 
print "area of a rectangle\n"
elsif choice == 3 then 
print "area of a circle\n"
print "enter radius of circle\n"
a = STDIN.gets.chomp.to_f
c = a*a*3.14159
print "area of circle = ",c,"\n"
elsif choice == 4 then 
quit = 1
end
end

Save the file as areasruby.rb
Run the script by typing ./areasruby.rb

Rexx:

Open a new document in any text editor (kwrite, kedit or kate).

Type the following lines:

#!/usr/bin/rexx
quit = 0
do while quit = 0
say "enter 1 for area of a square, 2 for area of a rectangle, 3 area of a circle and 4 to quit"
pull a
if a = 1 then
do
say "enter base length of square"
pull b
c = b*b
say "area of square = " c
end
if a = 2 then
do
say "area of a rectangle"
say "enter base length of rectangle"
pull b
say "enter height of rectangle"
pull b1
c = b*b1
say "area of rectangle = " c
end
if a = 3 then
do
say "area of a circle"
say "enter radius of circle"
pull b
c = b*b*3.14159
say "area of circle = " c
end
if a = 4 then 
do
quit = 1
end
end

Save the file as areasrexx.rexx
Run the script by typing ./areasrexx.rexx

More programs and examples (related to electrical power systems):

The above pages will be updated frequently.

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