This is a good summary of many common MATLAB commands. It is reproduced here in HTML format.
Source: PDF file posted at several sites but originally created by Dr. Brian Vick of Virginia Tech.
Index
General Purpose Commands
Operators and Special Characters
+ 
Plus;
addition operator. 
 
Minus;
subtraction operator. 
* 
Scalar
and matrix multiplication operator. 
.* 
Array
multiplication operator. 
^ 
Scalar
and matrix exponentiation operator. 
.^ 
Array
exponentiation operator. 
\ 
Leftdivision
operator. 
/ 
Rightdivision
operator. 
.\ 
Array
leftdivision operator. 
./ 
Array
rightdivision operator. 
: 
Colon;
generates regularly spaced elements and represents an entire row or column. 
( ) 
Parentheses;
encloses function arguments and array indices; overrides precedence. 
[ ] 
Brackets;
enclosures array elements. 
. 
Decimal
point. 
… 
Ellipsis;
linecontinuation operator. 
, 
Comma;
separates statements and elements in a row. 
; 
Semicolon;
separates columns and suppresses display. 
% 
Percent
sign; designates a comment and specifies formatting. 
’ 
Quote
sign and transpose operator. 
.’ 
Nonconjugated
transpose operator. 
= 
Assignment
(replacement) operator. 
Commands for Managing a Session
clc 
Clears
Command window. 
clear 
Removes
variables from memory. 
exist 
Checks
for existence of file or variable. 
global 
Declares
variables to be global. 
help 
Searches
for a help topic. 
lookfor 
Searches
help entries for a keyword. 
quit 
Stops
MATLAB. 
who 
Lists
current variables. 
whos 
Lists
current variables (long display). 
Special Variables and Constants
ans  Most recent answer 
eps  Accuracy of floatingpoint precision 
i,j  The imaginary unit sqrt(1) 
Inf  Infinity 
NaN  Undefined numerical result (not a number) 
pi  The number 3.14159... 
System and File Commands
cd 
Changes
current directory. 
date 
Displays
current date. 
delete 
Deletes a
file. 
diary 
Switches
on/off diary file recording. 
dir 
Lists all
files in current directory. 
load 
Loads
workspace variables from a file. 
path 
Displays
search path. 
pwd 
Displays
current directory. 
save 
Saves
workspace variables in a file. 
type 
Displays
contents of a file. 
what 
Lists all
MATLAB files in the current directory. 
wklread 
Reads
.wk1 spreadsheet file. 
Input/Output and Formatting Commands
Input/Output Commands
disp 
Displays
contents of an array or string. 
fscanf 
Read
formatted data from a file. 
format 
Controls
screendisplay format. 
fprintf 
Performs formatted writes to screen or file. 
sprintf 
Performs formatted writes to a text variable. 
input 
Displays
prompts and waits for input. 
; 
Suppresses
screen printing. 
[txt1 txt2 'literal'] 
Concatenate text 
{ txt1, txt2, 'literal' } 
Use a cell array to represent multiline text 
Format Codes for fprintf and fscanf
Format Codes for fprintf and fscanf 
%s 
Format as
a string. 
%d 
Format as
an integer. 
%f 
Format as
a floating point value. 
%e 
Format as
a floating point value in scientific notation. 
%g 
Format in
the most compact form: %f or %e. 
\n 
Insert a
new line in the output string. 
\t 
Insert a
tab in the output string. 
Numeric Display Format
format short 
Four
decimal digits (default). 
format long 
16
decimal digits. 
format short e 
Five
digits plus exponent. 
format long
e 
16 digits
plus exponents. 
format bank 
Two
decimal digits. 
format + 
Positive,
negative, or zero. 
format rat 
Rational
approximation. 
format compact 
Suppresses
some line feeds. 
format loose 
Resets to
less compact display mode. 
Vector, Matrix and Array Commands
Array Commands
cat 
Concatenates
arrays. 
find 
Finds
indices of nonzero elements. 
length 
Computers
number of elements. 
linspace 
Creates
regularly spaced vector. 
logspace 
Creates
logarithmically spaced vector. 
max 
Returns
largest element. 
min 
Returns
smallest element. 
prod 
Product
of each column. 
reshape 
Change
size 
size 
Computes
array size. 
sort 
Sorts
each column. 
sum 
Sums each
column. 
Special Matrices
eye 
Creates
an identity matrix. 
ones 
Creates
an array of ones. 
zeros 
Creates
an array of zeros. 
Matrix Arithmetic
cross 
Computes
cross products. 
dot 
Computes
dot products. 
Matrix Commands for Solving Linear Equations
det 
Computes
determinant of an array. 
inv 
Computes
inverse of a matrix. 
pinv 
Computes
pseudoinverse of a matrix. 
rank 
Computes
rank of a matrix. 
rref 
Computes
reduced row echelon form. 
Cell Array Functions
cell 
Creates
cell array. 
celldisp 
Displays
cell array. 
cellplot 
Displays
graphical representation of cell array. 
num2cell 
Converts
numeric array to cell array. 
deal 
Matches
input and output lists. 
iscell 
Identifies
cell array. 
Structure Functions
fieldnames 
Returns
field names in a structure array. 
getfield 
Returns
field contents of a structure array. 
isfield 
Identifies
a structure array field. 
isstruct 
Identifies
a structure array. 
rmfield 
Removes a
field from a structure array. 
setfield 
Sets
contents of field. 
struct 
Creates
structure array. 
Plotting Commands
Basic xy Plotting Commands
axis 
Sets axis
limits. 
fplot 
Intelligent
plotting of functions. 
grid 
Displays
gridlines. 
plot 
Generates
xy plot. 
print 
Prints
plot or saves plot to a file 
title 
Puts text
at top of plot. 
xlabel 
Adds text
label to xaxis. 
ylabel 
Adds text
label to yaxis. 
Plot Enhancement Commands
axes 
Creates
axes objects. 
close 
Closes
the current plot. 
close all 
Closes
all plots. 
figure 
Opens a
new figure window. 
gtext 
Enables
label placement by mouse. 
hold 
Freezes
current plot. 
legend 
Legend
placement by mouse. 
refresh 
Redraws
current figure window. 
set 
Specifies
properties of objects such as axes. 
subplot 
Creates
plots in subwindows. 
text 
Places
string in figure. 
Specialized Plot Commands
bar 
Creates
bar chart. 
loglog 
Creates
loglog plot. 
polar 
Creates
polar plot. 
semilogx 
Creates
semilog plot (logarithmic abscissa). 
semilogy 
Creates
semilog plot (logarithmic ordinate). 
stairs 
Creates
stairs plot. 
stem 
Creates
stem plot. 
Colors, Symbols and Line Types
Color 

Symbol 

Line 
y 
yellow 
. 
point 
 
solid 
m 
magenta 
o 
circle 
: 
dotted 
c 
cyan 
x 
xmark 
. 
dash
dotted 
r 
red 
+ 
plus 
 
dashed 
g 
green 
* 
star 


b 
blue 
d 
diamond 
w 
white 
v 
triangle
(down) 
k 
black 
^ 
triangle
(up) 

< 
triangle
(left) 
> 
triangle
(right) 
p 
pentagram 
h 
hexagram 
ThreeDimensional Plotting Commands
contour 
Creates
contour plot. 
mesh 
Creates
threedimensional mesh surface plot. 
meshc 
Same as
mesh with contour plot underneath. 
meshz 
Same as
mesh with vertical lines underneath. 
plot3 
Creates
threedimensional plots from lines and points. 
surf 
Creates
shaded threedimensional mesh surface plot. 
surfc 
Same as
surf with contour plot underneath. 
meshgrid 
Creates
rectangular grid. 
waterfall 
Same as
mesh with mesh lines in one direction. 
zlabel 
Adds text
label to zaxis. 
Histogram Functions
bar 
Creates a
bar chart. 
hist 
Aggregates
the data into equally spaced bins. 
histc 
Aggregates
the data into unequally spaced bins. 
Programming
Logical and Relational Operators
== 
Relational
operator: equal to. 
~= 
Relational
operator: not equal to. 
< 
Relational
operator: less than. 
<= 
Relational
operator: less than or equal to. 
> 
Relational
operator: greater than. 
>= 
Relational
operator: greater than or equal to. 
& 
Logical
operator: AND. 
 
Logical
operator: OR. 
~ 
Logical
operator: NOT. 
xor 
Logical
operator: EXCLUSIVE OR. 
Program Flow Control
break 
Terminates
execution of a loop. 
case 
Provides
alternate execution paths within switch structure. 
else 
Delineates
alternate block of statements. 
elseif 
Conditionally
executes statements. 
end 
Terminates
for, while, and if statements. 
error 
Display
error messages. 
for 
Repeats
statements a specific number of times 
if 
Executes
statements conditionally. 
otherwise 
Default
part of switch statement. 
return 
Return to
the invoking function. 
switch 
Directs
program execution by comparing point with case expressions. 
warning 
Display a
warning message. 
while 
Repeats
statements an indefinite number of times. 
Logical Functions
any 
True if
any elements are nonzero. 
all 
True if
all elements are nonzero. 
find 
Finds
indices of nonzero elements. 
finite 
True if
elements are finite. 
isnan 
True if
elements are undefined. 
isinf 
True if
elements are infinite. 
isempty 
True if
matrix is empty. 
isreal 
True if
all elements are real. 
MFiles
eval 
Interpret
strings containing Matlab expressions. 
feval 
Function
evaluation. 
function 
Creates a
userdefined function Mfile. 
global 
Define
global variables. 
nargin 
Number of
function input arguments. 
nargout 
Number of
function output arguments. 
varargin 
Cell array that will allow for a variable number of function inputs. 
nargout 
Cell array that will allow for a variable number of function outputs. 
script 
Script
Mfiles 
Timing
cputime 
CPU time
in seconds. 
clock 
Current
date and time as date vector. 
tic, toc 
Start,
stop a stopwatch timer. 
Mathematical Functions
Exponential and Logarithmic Functions
Square root
exp(x)  Exponential; e^{x} 
log(x)  Natural logarithm; ln(x) 
log10(x)  Common (base 10) logarithm; log(x) = log10(x) 
sqrt(x) 

Trigonometric Functions
Note: these functions assume/return angle values in radians.
There are similar functions (suffixed with a d) that work in degrees.
See the help file for details.
acos(x) 
Inverse
cosine; arcos x = cos ^{–1} (x). 
acot(x) 
Inverse
cotangent; arccot x = cot ^{–1}(x). 
acsc(x) 
Inverse
cosecant; arcs x = csc ^{–1} (x). 
asec(x) 
Inverse
secant; arcsec x = sec ^{–1 }(x). 
asin(x) 
Inverse
sine; arcsin x = sin ^{–1} (x). 
atan(x) 
Inverse
tangent; arctan x = tan ^{–1} (x). 
atan2(y,x) 
Fourquadrant
inverse tangent. 
cos(x) 
Cosine;
cos(x). 
cot(x) 
Cotangent;
cot(x). 
csc(x) 
Cosecant;
csc(x). 
sec(x) 
Secant;
sec(x). 
sin(x) 
Sine;
sin(x). 
tan(x) 
Tangent;
tan(x). 
Hyperbolic Functions
acosh(x) 
Inverse
hyperbolic cosine; cosh ^{–1} (x). 
acoth(x) 
Inverse
hyperbolic cotangent; coth ^{–1} (x). 
acsch(x) 
Inverse
hyperbolic cosecant; csch ^{–1 }(x). 
asech(x) 
Inverse
hyperbolic secant; sech ^{–1 }(x). 
asinh(x) 
Inverse
hyperbolic sine; sinh ^{–1} (x). 
atanh(x) 
Inverse
hyperbolic tangent; tanh ^{–1} (x). 
cosh(x) 
Hyperbolic
cosine; cosh(x). 
coth(x) 
Hyperbolic
cotangent; cosh(x)/sinh(x). 
csch(x) 
Hyperbolic
cosecant; 1/sinh(x). 
sech(x) 
Hyperbolic
secant; 1/cosh(x). 
sinh(x) 
Hyperbolic
sine; sinh(x). 
tanh(x) 
Hyperbolic
tangent; sinh(x)/cosh(x). 
Complex Functions
abs(x) 
Absolute
value; x. 
angle(x) 
Angle of
a complex number x. 
conj(x) 
Complex
conjugate of x. 
imag(x) 
Imaginary
part of a complex number x. 
real(x) 
Real part
of a complex number x. 
Statistical Functions
erf(x) 
Computes
the error function erf (x). 
mean 
Calculates
the average. 
median 
Calculates
the median. 
std 
Calculates
the standard deviation. 
Random Number Functions
rand 
Generates
uniformly distributed random numbers between 0 and 1. 
randn 
Generates
normally distributed random numbers. 
Numeric Functions
ceil 
Rounds to
the nearest integer toward •. 
fix 
Rounds to
the nearest integer toward zero. 
floor 
Rounds to
the nearest integer toward  •. 
round 
Rounds
towards the nearest integer. 
sign 
Signum
function. 
String Functions
findstr 
Finds
occurrences of a string. 
strcmp 
Compares
strings. 
char 
Creates
character string array 
Numerical Methods
Polynomial and Regression Functions
conv 
Computes
product of two polynomials 
deconv 
Computes
ratio of polynomials. 
eig 
Computes
the eigenvalues of a matrix. 
poly 
Computes
polynomial from roots. 
polyfit 
Fits a
polynomial to data. 
polyval 
Evaluates
polynomial and generates error estimates. 
roots 
Computes
polynomial roots. 
Interpolation Functions
interp1 
Linear
and cubicspline interpolations of a function of one variable. 
interp2 
Linear
interpolation of a function of two variables. 
spline 
Cubicspline
interpolation. 
unmkpp 
Computes
the coefficients of cubicspine polynomials. 
Root Finding and Minimization
fmin 
Finds
minimum of singlevariable function. 
fmins 
Finds
minimum of multivariable function. 
fzero 
Finds
zero of singlevariable function. 
Numerical Integration Functions
quad 
Numerical
integration with adaptive Simpson’s rule. 
quadl 
Numerical
integration with adaptive Lobatto quadrature. 
trapz 
Numerical
integration with the trapezoidal rule. 
Numerical Differentiation Functions
diff(x) 
Computes
the difference between adjacent elements in the vector x. 
polyder 
Differentiates
a polynomial, a polynomial product, or a polynomial quotient. 
ODE Solvers
ode23 
Nonstiff,
loworder solver. 
ode45 
Nonstiff,
mediumorder solver. 
ode113 
Nonstiff,
variableorder solver. 
ode23s 
Stiff,
loworder. 
ode23t 
Moderately
stiff, trapezoidal rule solver. 
ode23b 
Stiff,
loworder solver. 
ode15s 
Stiff,
variableorder solver. 
odeset 
Creates
integrator options structure for ODE solvers. 
Predefined Input Functions
gensig 
Generates
a periodic sine, square, or pulse input. 
sawtooth 
Generates
a periodic sawtooth input. 
square 
Generates
a square wave input. 
stepfun 
Generates
a step function input. 
Symbolic Math Toolbox
Functions for Creating and Evaluating Symbolic Expressions
class 
Returns
the class of an expression. 
digits 
Sets the
number of decimal digits used to do variable precision arithmetic. 
double 
Converts
an expression to numeric form. 
ezplot 
Generates
a plot of a symbolic expression. 
findsym 
Finds the
symbolic variables in a symbolic expression. 
numden 
Returns
the numerator and denominator of an expression. 
sym 
Creates a
symbolic variable. 
syms 
Creates
one or more symbolic variables. 
vpa 
Sets the
number of digits used to evaluate expressions. 
Functions for Manipulating Symbolic Expressions
collect 
Collects
coefficients of like powers in an expression. 
expand 
Expands
an expression by carrying out jpowers. 
factor 
Factors
an expression. 
poly2sym 
Converts
a polynomial coefficient vector to a symbolic polynomial. 
pretty 
Displays
an expression in a form that resembles typeset mathematics. 
simple 
Searches
for the shortest form of an expression. 
simplify 
Simplifies
an expression using Maple’s simplification rules. 
subs 
Substitutes
variables or expressions. 
sym2poly 
Converts
an expression to a polynomial coefficient vector. 
Symbolic Calculus Functions
diff 
Returns
the derivative of an expression. 
Dirac 
Dirac
delta function (unit impulse). 
Heaviside 
Heaviside
function (unit step). 
int 
Returns
the integral of an expression. 
limit 
Returns
the limit of an expression. 
symsum 
Returns
the symbolic summation of an expression. 
taylor 
Returns
the Taylor series of a function. 
Symbolic Solution of Algebraic and Transcendental Equations
solve 
Solves
symbolic equations. 
Symbolic Solution of Differential Equations
dsolve 
Returns a
symbolic solution of a differential equation or set of equations. 
Laplace Transform Functions
ilaplace 
Returns
the inverse Laplace transform. 
laplace 
Returns
the Laplace transform. 
Symbolic Linear Algebra Functions
det 
Returns
the determinant of a matrix. 
eig 
Returns
the eigenvalues (characteristic roots) of a matrix. 
inv 
Returns
the inverse of a matrix. 
poly 
Returns
the characteristic polynomial of a matrix. 