10 Installed scripts ¶

Gnuastro’s programs (introduced in previous chapters) are designed to be highly modular and thus contain lower-level operations on the data. However, in many contexts, certain higher-level are also shared between many contexts. For example, a sequence of calls to multiple Gnuastro programs, or a special way of running a program and treating the output. To facilitate such higher-level data analysis, Gnuastro also installs some scripts on your system with the (astscript-) prefix (in contrast to the other programs that only have the ast prefix).

Like all of Gnuastro’s source code, these scripts are also heavily commented. They are written in portable shell scripts (command-line environments), which does not need compilation. Therefore, if you open the installed scripts in a text editor, you can actually read them²³⁹. For example, with this command (just replace nano with your favorite text editor, like emacs or vim):

$ nano $(which astscript-NAME)

Shell scripting is the same language that you use when typing on the command-line. Therefore shell scripting is much more widely known and used compared to C (the language of other Gnuastro programs). Because Gnuastro’s installed scripts do higher-level operations, customizing these scripts for a special project will be more common than the programs.

These scripts also accept options and are in many ways similar to the programs (see Common options) with some minor differences:

• Currently they do not accept configuration files themselves. However, the configuration files of the Gnuastro programs they call are indeed parsed and used by those programs.

  As a result, they do not have the following options: --checkconfig, --config, --lastconfig, --onlyversion, --printparams, --setdirconf and --setusrconf.

• They do not directly allocate any memory, so there is no --minmapsize.
• They do not have an independent --usage option: when called with --usage, they just recommend running --help.
• The output of --help is not configurable like the programs (see --help).
• The scripts will commonly use your installed shell and other basic command-line tools (for example, AWK or SED). Different systems have different versions and implementations of these basic tools (for example, GNU/Linux systems use GNU Bash, GNU AWK and GNU SED which are far more advanced and up to date then the minimalist AWK and SED of most other systems). Therefore, unexpected errors in these tools might come up when you run these scripts on non-GNU/Linux operating systems. If you do confront such strange errors, please submit a bug report so we fix it as soon as possible (see Report a bug).

• Sort FITS files by night
• Generate radial profile
• SAO DS9 region files from table
• Viewing FITS file contents with DS9 or TOPCAT
• Zero point estimation
• Pointing pattern simulation
• Color images with gray faint regions
• PSF construction and subtraction