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Introduction
1. Introduction to the UNIX Operating System
- 1.1. What is UNIX?
- 1.2. Types of Unix
- 1.3. The UNIX operating system
- 1.4. Files and processes
- 1.5. The Directory Structure
- 1.6. Starting an UNIX terminal
2. Tutorial One
- 2.1. Listing files and directories
- 2.2. Making Directories
- 2.3. Changing to a different Directory
- 2.4. The directories . and ..
- 2.5. Pathnames
- 2.6. More about home directories and pathnames
- 2.7. Summary
3. Tutorial Two
- 3.1. Creating files
- 3.2. Copying Files
- 3.3. Moving Files
- 3.4. Removing Files and directories
- 3.5. Displaying the contents of a file on the screen
- 3.6. Searching the contents of a file
- 3.7. Summary
4. Tutorial Three
- 4.1. Redirection
- 4.2. Redirecting the Input
- 4.3. Redirecting the Output
- 4.4. Pipes
- 4.5. Summary
5. Tutorial Four
- 5.1. Wildcards
- 5.2. Filename Conventions
- 5.3. Getting Help
- 5.4. Summary
6. Tutorial Five
- 6.1. File system security (access rights)
- 6.2. Changing access rights
- 6.3. Processes and Jobs
- 6.4. Listing suspended and background processes
- 6.5. Killing a process
- 6.6. Summary
7. Tutorial Six
- 7.1. Other useful Unix commands
- 7.2. Summary
8. Tutorial Seven
- 8.1. Compiling UNIX software packages
- 8.2. Download source code
- 8.3. Extracting source code
- 8.4. Configuring and creating the Makefile
- 8.5. Building the package
- 8.6. Running the software
- 8.7. Stripping unnecessary code
- 8.8. Summary
9. Tutorial Eight
- 9.1. UNIX variables
- 9.2. Environment variables
- 9.3. Shell variables
- 9.4. Using and setting variables
- 9.5. Setting shell variables in the .cshrc file
- 9.6. Setting the path
- 9.7. Summary
10. Tutorial Nine
- 10.1. What is *vi*?
- 10.2. Essential commands
- 10.3. Practical introduction to *vim*
11. Tutorial Ten
- 11.1. Introduction to shell script
- 11.2. Create and execute a script
- 11.3. Passing parameters to the shell
12. Annex I: basic commands
13. Annex II: First steps with Erle
14. Annex III: Network connection with Erle
- 14.1. Connecting with Erle
- 14.2. A new Erle-terminal
- 14.3. Transferring files form your computer to Erle

Erle Robotics Unix Introduction Gitbook Free

Passing parameters to the shell

Parameter	Meaning
$0	value of the executed command itself
$1	value of the 1st parameter
$2,$3 ...	value of the 2nd, 3rd...parameter
$#	number of parameters
$*	value of all concatened parameters

For understanding better the table above, let's do a simply exercise. Create a file called parameters.And edit it(we recommend you using vi parameters) with the following content:

echo 'param. number=' $#
echo '$0=' $0
echo '$1=' $1
echo '$2=' $2
echo '$3=' $3
echo '$*=' $*

Now, change the permissions using

chmod +x parameters

And execute the script with different parameters:

./parameters (no parameters)
./parameters hello (one parameter)
./parameters pa1 pa2 pa3 (three parameters)

working with erlerobot:

param