GNU Astronomy Utilities

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4.1 Command-line

All the programs in Gnuastro are customized through the standard GNU style command-line options. Thus, we’ll start by defining this general style that is very common in many command-line tools on Unix-like operating systems. Finally, the options that are common to all the programs in Gnuastro are discussed.

The command-line text that you type is passed onto the shell (or program managing the command-line) as a string of characters. See the “Invoking ProgramName” sections in this manual for some examples of commands with each program, for example Invoking Table. That string is then broken up into separate tokens or words by any metacharacters (like space, tab, |, > or ;) that might exist in the text. To learn more, please see the GNU Bash manual, for the complete list of meta-characters and other GNU Bash definitions (GNU Bash is the most common shell program). Its “Shell Operation” section has a short summary of the steps the shell takes before passing the commands to the program you called.