Initialization of GENSYS general

The UNIX environment

Reasons why GENSYS runs under UNIX:

The GENSYS software package is a very old, the beginning of the development started already in 1971.
UNIX was from the beginning designed for large programs, large computers, multiuser and multitasking. Windows programs were very long time limited to 640kb.
UNIX filenames may contain up to 255 characters, with a maximum path of 4096 characters. Windows programs were very long time limited to 8 + 3 characters, with a maximum path of 256 characters.
UNIX is very stable operating system because it is designed for many user running on mainframe computers
UNIX includes many advanced tools like: batch execution, queue-system, remote login, send jobs to other computers, file comparison, file permissions, file searching, searching for expressions in files, string editor, regular expression,,, etc.

However by running gensys in a virtual machine under VirtualBox. The problem with different operating systems has now easily been overcome. Now gensys runs on all machines where VirtualBox is installed.

Most important differences between UNIX and Windows:

Program EXPLORER.EXE does not exists in UNIX. Please use program "caja" instead.

The mouse has three buttons:

Left button	Sets the contents of buffer PRIMARY SELECTION
Middle button	Paste the contents of buffer PRIMARY SELECTION
Right button	Pops up the background menu of the program (if the program has a background menu)

PRIMARY SELECTION is copied to CLIPBOARD by pressing CTRL+Ins.
CLIPBOARD is pasted by pressing SHIFT+Ins.
However, in many programs CTRL+Ins equals CTRL+C, and SHIFT+Ins equals CTRL+V.
But in terminal windows this doesn't work, because in terminal windows CTRL+C means interrupt and CTRL+V means "Insert next non-digit literally". Therefore terminal windows are often using the keyboard short-cuts SHIFT+CTRL+C and SHIFT+CTRL+V instead.
Moving windows are made with "Alt+Mouse Button #1".
Resizing windows are made with "Alt+Mouse Button #3".
Moving scrollbars work best with "Mouse Button #2".
Filenames in UNIX can consist of more than one period ".". A period in a UNIX filenames is just an ordinary character, like "a", "b",,, etc.
Filenames in UNIX that starts with a period "." are hidden files. To see them the user can write "ls .*" or "ls -a"
Line terminators in Windows-files consists of both a newline and a carriage_return (CRLF). UNIX-files have only a newline(NL). The following two scripts can be used to translate in between the two formats:

dos2ux Translates from DOS to UNIX
ux2dos Translates from UNIX to DOS

Useful UNIX commands:

ls
Command ls lists files in current directory.
Command "opman ls" gives you the full manual of the ls-script.
li
Without argument command li is exactly the same as ls above. With argument command li behaves different. Script li searches for all files in current and all subdirectories matching the search expression given in the argument.
cd
Command cd changes current directory.
Command cd .. changes to parent directory.
Command cd - changes to previous directory.
Command cd is a shell builtin. In order to read the documentation of cd write "opman bash".
egrep
The egrep utility searches one or more files, line by line, for a pattern.
Example: Lists all occasions of "search text" in all files with extension .txt
egrep 'search text' *.txt
Command "opman egrep" gives you the full manual of the egrep-script.

regular expression
The "search text" under egrep above is called regular expression. The following characters have special meanings in a regular expression:

^	The beginning of the line
$	The end of the line
[xy]	Matches both x and y.
[a-z]	Matches all lower case letter.
[0-9]	Matches all numbers.
[^x]	Matches any character except x.
.	Any character.
*	Repeats the character in front of the *-sign, the character will be repeated zero or more times.
\	Quote the next character. Example: if you are searching for a $-sign you must write \$ in the search expression.

For further information regarding regular expression, see http://en.wikipedia.org/wiki/Regular_expression

sed
Script sed is a non-interactive text editor. Sed is useful for doing many changes automatically. Example:
sed "s/old text/new text/" old_file > new_file
Command "opman sed" gives you the full manual of the sed-script.
A tutorial can be found on the Internet at http://www.grymoire.com/Unix/Sed.html.
tar
The tar utility creates, list tables of contents and extract files from an archive file.

Create: tar -ckz -f archive.tgz <files and directories>
TOC: tar -tkz -f archive.tgz
Extract: tar -xkz -f archive.tgz
Command "opman tar" gives you the full manual of the tar-script.
If you want to overwrite existing files you must omit option -k

Other useful commands can be found under Scripts used in the GENSYS package.

Special characters in UNIX:

Sign	Explanation	Example
>	Send the output from a command to a file	ls > my_dir.txt
>>	Appends the output from a command to a file	ls -l >> my_dir.txt
<	Read input data from a file	cat < my_dir.txt
<<+	Read input data direct after the +-sign until the next +-sign	cat <<+ The brown fox jumped over the lazy dog. +
\|	Pipe the output from a command to a second command	ps -ef \| grep $USER
\| cc	Pipe the output from a command to CLIPBOARD	ls \| cc
echo `vc`	To see the contents of the CLIPBOARD in a terminal
`vc`	Paste CLIPBOARD to terminal

Environment variables in UNIX:

Name	Explanation
$HOME	Name of home directory
$PATH	The user's search path for commands
$PWD	Name of current directory
$USER	User name

All defined environment variables can be viewed in with the UNIX env-command. New environment variables can be introduced with the UNIX export-command.

Handeling windows in UNIX:

Alt+Btn_1	Move window
Alt+Btn_3	Resize window

Title bar

Double click Btn 1	Rolls up and down the window
Btn 2	Lower the window

dos2ux		Translates from DOS to UNIX
ux2dos		Translates from UNIX to DOS

Create:	tar -ckz -f archive.tgz <files and directories>
TOC:	tar -tkz -f archive.tgz
Extract:	tar -xkz -f archive.tgz