|AHELP for CIAO 4.2||
The .ciaorc file provides user-configuration options for CIAO
When CIAO is started up - by sourcing the ciao.*sh file - it uses the .ciaorc file in your home directory to see if you have over-ridden several default values for choice of language (e.g. S-Lang or Python) and the location of various applications (such as slsh, ipython, or ds9). If the file does not exist then a default version will be created by the CIAO configuration script. The .ciaorc file is a simple text file that can be edited in a text editor. Blank lines and ones beginning with the '#' character are ignored.
When CIAO is started up, the CIAO_SCRIPT_LANG environment variable is set to the contents of the corresponding line in the ~/.ciaorc file. The valid choices are
If there is no setting in ~/.ciaorc then python is used.
The value of the CIAO_SCRIPT_LANG environment variable determines which language is used by the interactive versions of ChIPS and Sherpa (unless explicitly given using the "-l" flag as described in "ahelp chips" and "ahelp sherpa"). It is also used by ahelp to determine which version of a help file to chose for those pages which have language-specific versions, such as ChIPS and Sherpa commands.
By default, CIAO uses the versions of Python and ipython that are packaged with CIAO. The PYTHON, IPYTHON, and PYTHON_PATH settings can be changed to point to different versions of these programs. These settings should only be changed by expert users.
Due to how the CIAO executables are called via wrapper scripts, the output "which python" (e.g. $ASCDS_INSTALL/bin/python) will look like the CIAO version is still being used no matter what value the settings have. To see which version of Python is actually being accessed, start Sherpa or ChIPS and use the sys.executable command:
chips-1> sys.executable ' /usr/bin/python'
Note that CIAO does not set the PYTHON_PATH when CIAO is sourced, only when an application that requires it is called. This makes it possible to use Python in a CIAO window without modifying the .ciaorc file by using the full path, e.g. /usr/bin/python.
The postpend or prepend option specifies how the CIAO additions should be added to an existing PYTHON_PATH. Only the "prepend" value is allowed when using CIAO Python, to make sure a function that CIAO needs is not accidentally superceded.
Changing the value to "postpend" is useful if you have a specialized Python environment and you are concerned that CIAO functions (e.g. numpy, pysl, or CIAO Python functions) might have a name that is already defined in your system. In this case, the CIAO function will be unavailable but your function will work. Only advanced Python users may need this option.
By default, CIAO uses the S-Lang interpreter (slsh) that is packaged with CIAO. The SLSH setting can be changed to point to a different version of this program. This setting should only be changed by expert users.
The default version of the ds9 display program used by CIAO is the one included within the CIAO distribution. The DS9 and XPA settings can be changed to point to different versions of these tools.
The default .ciaorc file contains the following entries:
# Uncomment line to force CIAO to use a specific version of tool # Only the following tools are supported. # PYTHON_PATH Default is prepend. Can only postpend if users copy # of python is used and line is uncommented. #PYTHON_PATH postpend # Replace CIAO with path to python to force use of local python #PYTHON CIAO # Replace CIAO with path to ipython This is only checked if a # non-CIAO copy of python is being used. #IPYTHON CIAO # Replace /usr/local/bin with path to ds9 to force use of local ds9 #DS9 /usr/local/bin # Replace CIAO with path to slsh to force use of local slsh #SLSH CIAO # Replace CIAO with path to xpa to force use of local xpa #XPA CIAO # app variables control the variables the versions of software # that the internal CIAO tools use (such as sherpa or chips) # Modify these at your own risk. To modify uncomment out the # line and replace CIAO with the path to your copy of the tool #APP_PYTHON CIAO #APP_IPYTHON CIAO #APP_SLSH CIAO # CIAO_SCRIPT_LANG default is python. Other option is slang #CIAO_SCRIPT_LANG slang