A comprehensive introduction to the IRAF system can be found in A Users Introduction to the IRAF Command Language. A brief description and a few examples are given below.
The command cl starts IRAF.
cfa#: cl
NOAO SUN/IRAF Revision 2.10.2EXPORT Tue Nov 17 19:44:29 MST 1992
This is the EXPORT version of Sun/IRAF V2.10.2 for SunOS-4.1.
Welcome to IRAF. To list the available commands, type ? or ??. To get
detailed information about a command, type `help command'. To run a
command or load a package, type its name. Type `bye' to exit a
package, or `logout' to get out of the CL. Type `news' to find out
what is new in the version of the system you are using. The following
commands or packages are currently defined:
adccdrom. euv. lists. proto. system.
asc. ftools. mem0. redshift. tables.
ctio. hrc. noao. saotdc. utilities.
dataio images. obsolete. softools. veta.
cbms. language. plot. stsdas. xray.
cl>
A few explanations about how to find your way in IRAF:
The IRAF user interface or command language is called the cl. The system is composed of `packages', each itself composed of packages and commands (`tasks'). The packages currently available are listed at the time IRAF is first called, as in the example above. To select a listed package or run a listed task, type its name. Names can be shortened to one or more letters if they uniquely identify the task.
To run a task, first load the package that contains it (``help taskname'' will display a help file which includes the name of the package in which the task can be found). When loading a package for the first time, the tasks under that package (the package menu) are automatically displayed. Several packages can be loaded at one time, the system will remember them all. However, it is good practice to unload unnecessary packages, to avoid running out of memory. Packages can be unloaded by typing bye. However, they can only be unloaded in reverse loading order. So, for example, if dataio has been loaded before noao, typing bye will unload noao. A second bye will unload dataio.
Every time a new package is selected, the prompt will change to reflect this selection.
To leave the IRAF environment type:
cl> logout cfa#