Initialization of GENSYS general

The UNIX environment

There are a number of reasons why GENSYS runs under UNIX:

The GENSYS software package is a very old, the beginning of the development started already in 1971.
UNIX is available for almost all computer sizes and brands.
UNIX was from the beginning designed for large programs, large computers, multiuser and multitasking.
UNIX is very stable operating system because it is designed for many user running on mainframe computers

For the user the difference between Windows, MacIntosh and UNIX are relatively small. The most important differences are:

The mouse has three buttons:
Left button sets the contents of buffer PRIMARY SELECTION.
Middle button pastes the contents of buffer PRIMARY SELECTION.
Right button pops up the background menu of the program (if the program has a background menu).
The PRIMARY SELECTION is copied to CLIPBOARD by pressing Ctrl-Ins.
CLIPBOARD is pasted by pressing Shift-Ins.
In many programs Shift-Ins equals Ctrl-C or Alt-c, and Shift-Ins equals Ctrl-V or Alt-v.
Scrolling scrollbars work best with the middle mouse button.
Windows files have both a newline and a carriage_return in the end of each line in a file. UNIX only has a newline character. In some cases it is necessary to remove the carriage_return characters.
In order to switch between DOS- and UNIX-format the user has access to the following two commands: dos2ux and ux2dos. These two scripts are located in directory $gensys/bin.

Useful UNIX commands:

Command ls lists all files in current directory.
Command cd changes current directory.
Command cd .. changes to parent directory.
Command cd - changes to previous directory.
The grep 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 grep 'search text' *.txt

The "search text" under grep 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
\	Quote the next character. Example: if you are searching for a $-sign you must write \$ in the search expression.
.	Any character
*	Repeats the character in front of the *-sign, the character will be repeated zero or more times.
[xy]	Matches both x and y.
[^x]	Matches any character except x.

For further information regarding the UNIX regular expression, please write the command opman re_syntax in a xterm- or genfile- window.

The sed is a non-interactive editor. The sed is useful for doing many changes automatically. Example:
sed "s/old text/new text/" old_file > new_file
The tar utility creates, list tables of contents and extract files from an archive file.

Create: tar cfz archive.tgz <files or directories>
TOC: tar tfz archive.tgz
Extract: tar xfz archive.tgz

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. +
\|	Send the output from a command to the next command	ps -ef \| grep $USER

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 2	Lower the window
Alt + Btn 3	Resize window

Create:	tar cfz archive.tgz <files or directories>
TOC:	tar tfz archive.tgz
Extract:	tar xfz archive.tgz