Commands

In our third lecture about MATLAB syntax we simply overview the 'commands' for managing the work session. Now we discuss all the commands one by one.

Commands for managing the work session:

>> The lists of commonly used general MATLAB commands are:

clc	Clears the Command window
clear	Removes all variables from memory.
clear v1 v2	Removes the variables v1 and v2 from memory.
exist ( ' var ' )	Determines if a file or variable exists having the name ‘var’.
quit	Stops MATLAB.
who	Lists the variables currently in memory.
whos	Lists the current variables and sizes, and indicates if they have imaginary parts.
exit	Exit MATLAB
global	Declares variables to be global.
help	Searches for a help topic.
lookfor	Searches help entries for a keyword.

Commands for Working with the System:

>> MATLAB provides various useful commands for working with the system, like saving the current work in the workspace as a file and loading the file later. It also provides various commands for other system-related activities like, displaying date, listing files in the directory, displaying current directory, The table shows some commonly used system-related 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 and Output Commands:

>> Following are the input and output related commands in MATLAB:

disp	Displays contents of an array or string.
fscanf	Read formatted data from a file.
format	Controls screen-display format.
fprintf	Performs formatted writes to screen or file.
input	Displays prompts and waits for input.
;	Suppresses screen printing.

>> This picture show you how 'DISP' command works. Open picture in new window and check the following outputs.

1. The black line shows how to simple display string.

2. The red line shows how to display two scalars on one line.

3. The yellow line simply display the transpose of vector x and y. Note ( ' ) symbol with x' and y' is used to taking transpose.

4. The blue line shows how to display string along with numeric data or stored value.

>> The fscanf and fprintf commands behave like C scanf and printf functions. They support the following format codes:

%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.

>> The format function has the following forms used for numeric display:

format short	Display up to Four decimal digits (default).
format long	Display up to 16 decimal digits.
format short e	Display up to  Five digits plus exponent.
format long e	Display up to 16 digits plus exponents.
format bank	Display up to Two decimal digits.
format +	Display up to Positive, negative, or zero.
format rat	Display up to Rational approximation.
format compact	Display up to Suppresses some line feeds.
formatloose	Display up to Resets to less compact display mode.

Vector, Matrix and Array Commands:

>> The following table shows various commands used for working with arrays, matrices and vectors:

cat	Concatenates arrays.
find	Finds indices of nonzero elements.
length	Computes 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	Changes size.
size	Computes array size.
sort	Sorts each column.
sum	Sums each column.
eye	Creates an identity matrix.
ones	Creates an array of ones.
zeros	Creates an array of zeros.
cross	Computes matrix cross products.
dot	Computes matrix dot products.
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	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.

Plotting Commands:

>> MATLAB provides numerous commands for plotting graphs. The following table shows some of the commonly used commands for plotting:

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 x-axis.
ylabel	Adds text label to y-axis.
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.
bar	Creates bar chart.
loglog	Creates log-log plot.
ploar	Creates polar plot.
semilogx	Creates semilog plot. (logarithmic abscissa).
semilogy	Creates semilog plot. (logarithmic ordinate).
stairs	Creates stairs plot.
stem	Creates stem plot.

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