3.1.7 Startup sequence

On start-up, SINGULAR

1. loads the library standard.lib (provided the --no-stdlib option was not given),

2. searches the current directory and then the home directory of the user, and then all directories contained in the library SearchPath (see Loading a library for more info on SearchPath) for a file named .singularrc and executes it, if found (provided the --no-rc option was not given),

3. executes the string specified with the --execute command line option,

4. executes the files file1, file2 ... (given on the command line) in that order.

Note: .singularrc file(s) are an appropriate place for setting some default values of (command-line) options.

For example, a system administrator might remove the locally installed HTML version of the manual and put a .singularrc file with the following content

if (system("version") >= 1306) // assure backwards-compatibility { system("--allow-net", 1); }; // the last semicolon is important: otherwise no ">", but "." prompt

in the directory containing the SINGULAR libraries, thereby allowing to fetch the HTML on-line help from the WWW home-site of SINGULAR.

On the other hand, a single user might put a .singularrc with the following content

if (system("version") >= 1306) // assure backwards-compatibility { if (! system("--emacs")) { // set default browser to info, unless we run within emacs system("--browser", "info"); } }; // the last semicolon is important: otherwise no ">", but "." prompt

in his home directory, which sets the default help browser to info (unless SINGULAR is run within emacs) and thereby prevents the execution of the"global" .singularrc file installed by the system administrator (since the .singularrc file of the user is found before the "global" .singularrc file installed by the system administrator).