User:Murthy j

IDL Resources
Basic Commands

Invoking IDL is dependent on the operating system, the variant of IDL and the local environment. The installation instructions should be consulted for details, including system variables which may control aspects of the program behavior. For example, my .bash_profile file (Mac OS X bash) contains the two lines (amongst other unrelated commands): export GDL_STARTUP="/Users/jayanth/user/idluser/GDL_STARTUP"

export GDL_PATH="+/Users/jayanth/user/idluser/idllib:/opt/local/share/gnudatalanguage/lib: The first of these instructs GDL to execute the commands in the GDL_STARTUP file as it starts up while the second gives the directories where GDL should look for library routines.

My startup file is as follows: journal; Keep a log of all input and output to the command line. Default is to save in a file called gdljournal.pro.

defsysv,"!red",255; Define a system variable called !red. We will look at the application of this later.

defsysv,"!green",65535; Define a system variable called !green.

!quiet=1; Operate in "quiet" mode. Don't tell me which programs are being compiled. Anything after the semicolon (;) will not be compiled by IDL and can used for program documentation. Although my startup file only contains four lines, it could have been more complex and might contain any commands that I run on every invocation of IDL.