Shortly: calc.pl  is a download-and-use terminal calculator.
It is handy, easily extendable, tape-like. It comes with
most of usual and some financial and physical functions. 
You will like it.


Yes, there is a lot of calculators for linux on the web.

Once I was looking for something simple, fast to use,
something where you can see the history of operations
(tape calculator like gtapecalc), with minimum use of mouse,  
I didnot succeed. Most of the calculators are GUI - means that
 functions you must use the mouse or learn some shortcuts. 

Non-GUIs look too complicated (like Easy Stack Calculator) or
look too simple (like lcalc).

There are "linux-built-in" things like bc (arbitrary
precision calculator language) or octave, but their purpose is 
a little bit different from what I wanted.

This simple, but powerfull calc.pl PERL calculator contains 
features, that comeout from everyday use. Lets name some:

• No instalation, just download.
  
• Runs in terminal = fast copy-paste and/or remote operation.
  
• Fast quit with Ctrl-c 
  
• Line editing, acces to previously issued commands
  
• Help command from prompt. Just type "help"
  
• Standard functions (goniometric, logs) and some special functions
  
• Default operations (repeating operations modes)
  
• some more...
  

Calculator is written in perl, based on perl's own formula evaluation
and using 'stty cbreak' keyboard control. Program has NO module
dependences, it is a simple one file script. This implies the requirements.
That means usual linux system that understands 'stty cbreak'
and perl interpreter (present on virtualy every linux distribution).
Tested on fedora, redhat 7.3, knoppix, dyne::bolic...

Shortly: Linux with perl.

Download it, unzip it (gunzip calc.pl.gz), change the execution
flag (chmod +x perl.pl), run it (./calc.pl). Preferably - copy it
to the $HOME/bin directory to be able to run it from everywhere.
(echo $PATH, if you want to see the directories that are searched
for executables).


Shortly: No instalation.

Suppose you have a calc.pl prompt.

4+5
         9.000000
*8
         72.000000
/12
         6.000000
**2
         36.000000
sqrt
         6.000000

/( 2**2 +3^3 - 3 -26)
         3.000000

You can work in radians or degrees, here is an example:

deg
goniometric in degrees
30
         30.000000
sin
         0.500000
rad
goniometric in radians
asin
         0.523599
/pi
         0.166667
*180
         30.000000
deg
goniometric in degrees
cos
         0.866025
acos
         30.000000
tan
         0.577350
atan
         30.000000

log(1E3)
         3.000000
10**
         1000.000000
ln(1000)
         6.907755
e**
         1000.000000
exp(6.907755)
         999.999721
pi
         3.141593
**2
         9.869604

You could see before, how the constant "e" or how 10 is
exponentiated to the last result value, or how you exponentiate the
last result value.

Exactly.  And this is also a weak point of it. Press twice ENTER
to clear the memory ( pressing once - you just print a break-line).

pi
         3.141593
-3
         0.141593 ...!substaction..
pi
         3.141593
space-3
         -3.000000e+00

Variables - always lowercase. Watch the different
ways to input the value to variable(s):

a=3
         3.000000
4
         4.000000
=b
         4.000000
sqrt(b**2+a**2)
         5.000000
(a,b)=(6,7+1)
         2.000000
sqrt(b^2+a**2)
         10.000000
c=
         10.000000
enter
---------------------------------
enter
================================= AC
c
         10.000000

Yes.

e=2.71828182845904523536
pi=3.141592653589


hbar=6.581E-22 MeV s
ev=1.602E-19 Coulomb (electron charge)
hbarc=197 MeV fm

offs=32 (column where to display the result)

You can easily add your own predefined variables by editing the fist
several lines of the program.

Well. There are two DEFAULT OPERATION modes. Again, there
is a danger - once you forget that you are in DO mode, you
get wrong results. Pay attention to the warnings on the right
side of the result. Remark the "..DO" warning, when default operation
mode is on

1st mode: write + and then enter (or - or *)

+
default operation defined: + (-x is operation!, not a negative number)
1
         1.000000 ..DO
1
         2.000000 ..DO
1
         3.000000 ..DO
+5
         11.000000 ..DO

enter
default operation cleared
---------------------------------
+++3.23
default operation defined: +++3.23 (-x is operation!, not a negative number)
1
         4.230000 ..DO
2
         5.230000 ..DO
1
         4.230000 ..DO
enter
default operation cleared
---------------------------------

Some financial specific:

GETINTER(0.01, 24, 100, 0,0)
interest=1% yearly   #-months=24  bias=100$  each-month=0$  each-year=0$
                             102.010000

GETINTER(0.01, 24, 0, 10,30)
interest=1% yearly   #-months=24  bias=0$  each-month=10$  each-year=30$
                             302.603514

Some physics specific:

Legendre polynomials (p0,p2,p4, p1,p3),

Conversion between reduced electromagnetic transition probability
and a halflife of the level: Bb2T12 Bw2T12 T122Bb

Conversion between reduced electromagnetic transition probabilities
in 3 different system units : efm <-> eb <-> wu ... B2B

Conversion between time of flight and energy of neutron: tof2e e2tof

Use "help" command to learn how to use these functions.
See constants section for predefined physical constants.

Some others:

Yes, you can input the time (angle) and get it back.
Imagine, you wake up at 6 oclock and you go to sleep
at 10pm.

22:0-6:0
         960.000000
:
         16:00
         960.000000

22:0:0-6:0:0
         57600.000000
::
         16:00:00
         57600.000000

Other operations:

I didnot mention some stuff, that is implemented in perl and 
works also here in a natural way. Like modulo (50%40), less or
greater (5>4 but who will use it?),  bit shift operators (8>>1),  
binary or (8|2) of binary and (8&2) operators.

Arrows and backspace and delete. 

Up and down arrows browse the history.
However, the keyboard doesnot have to always
correspond. For this case, there are also
classical keypresses 

Ctrl-a, Ctrl-e (begin,end),
Ctrl-u,Ctrl-v (up,down),

Yes. If you end with three presses of enter, it writes the history
to the $HOME/.calc.pl

Well, there is a field @functions=qw(...).
Add you function name there.

Then there is a part labeled with 'NO ARGUMENT - TRANSLATE
you can add your function following the examples. This is
for what happens if the function is issued without an argument.

And then simply write your subroutine in the manner as can be seen
in others. Something like sub E2TOF{ ... return $result;}

No. But there is a nice piece of soft, mathomatic. You download,
compile and you can call it from inside calc.pl by issuing a command 
"mat".
( may need some libreadline.so.4 )