IDL Tips & Tricks
General: At the present state all the things here apply to the command line version of IDL on UNIX platforms. I don't use the IDL Development Environment because I don't like it at all. Programming is easier with the IDL/NEdit combination in my opinion. Nevertheless most of the tips are just general.
IDL Environment:
What is the startup file? In the startup file you can place some IDL commands which are executed every time you enter IDL. It can be any file in your file system, its name can be specified by the environment variable "IDL_STARTUP". For example (in Linux), you can add to your .bashrc file in your home directory the line "export IDL_STARTUP = /your/path/startup.pro". If you use another shell it might be a bit different.
What to do if you want to use your own routines just like the internal ones of IDL, i.e. without explicitly compiling them? Just put them all in a certain directory and add the following to your startup file: "!path=!path+':/the/path/to/your/dir". Of course you can specify several directories.
History too short? You want to have more than 20 commands in the buffer which can be reached with the cursor-up key? To get for example 100 add the following to your startup file: "!edit_input = 100"
Graphic Output:
If IDL do not want to switch to private color map on 8-bit displays, type directly after entering IDL the command "device,pseudo=8", and directly after "window,colors=255".
If the content of graphic windows disappear after another window was in front of it, use the command "device,retain=2".
Only black&white images on a true color screen? Several things might bring the solution. Try one or several of the following: "device,bypass=0/1", "device,decompose=0/1", "device,true=24"
Editors:
Do you like NEdit as an editor (like me)? Of course, it is the best for all who don't like to use Xemacs and vi and hate the stupid IDLDE. No, nedit does not run under Windows... I have made a syntax highlighting file for IDL programs as well as some macros, which might be useful also for LaTex users. Download this "nedit" and this "neditmacro" files, rename them to ".nedit" and ".neditmacro" and place them in your home directory. Be careful: This will overwrite your NEdit settings. If you dont like this you have to copy the appropriate parts of the files by yourself.
Hyperhelp:
The IDL Online Help does not work on plain installations of newer Linux distributions (SuSE >=7.0). Install the old libc5 compatibility libraries, they should be on your Linux CD. Mamma mia, 50MB of useless libs only because the hyperhelp use some very old binaries. Guys, please recompile soon.
Have a new tip/trick?