1#!/bin/bash
2
3# Universal bash program setup functions.
4
5# Example usage:
6
7# Source files to get required functions.
8# source_files="gen_setup.sh"
9# source_file_paths=$(type -p ${source_files})
10# for file_path in ${source_file_paths} ; do source ${file_path} ; done
11
12# Turn on extended globbing.
13shopt -s extglob
14
15
16function get_pgm_path_info() {
17    local program_path_var="${1:-program_path}" ; shift
18    local program_name_var="${1:-program_name}" ; shift
19    local program_dir_path_var="${1:-program_dir_path}" ; shift
20    local follow_links="${1:-0}" ; shift
21
22    # Determine the program path, name and dir path and assign them to the variables indicated by the caller.
23
24    # Description of argument(s):
25    # program_path_var                The name of the variable to receive the program path.
26    # program_name_var                The name of the variable to receive the program name.
27    # program_dir_path_var            The name of the variable to receive the program dir path.
28    # follow_links                    If the program running is actually a link to another file, use that file
29    #                                 when calculating the above values.
30
31    local _spn_loc_program_path_="${0}"
32
33    # The program name is the program path minus all characters up to and including the first slash.
34    local _spn_loc_program_name_=${_spn_loc_program_path_##*/}
35    # The program dir path is the program path minus everything from the last slash to the end of the string.
36    local _spn_loc_program_dir_path_=${_spn_loc_program_path_%${_spn_loc_program_name_}}
37
38    # If program dir path does not start with a slash then it is relative.  Convert it to absolute.
39    if [ "${_spn_loc_program_dir_path_:0:1}" != "/" ] ; then
40        _spn_loc_program_dir_path_="$(readlink -f ${_spn_loc_program_dir_path_})/"
41        # Re-assemble the parts into program path variable.
42        _spn_loc_program_path_="${_spn_loc_program_dir_path_}${_spn_loc_program_name_}"
43    fi
44
45    if (( follow_links )) ; then
46        _spn_loc_program_path_=$(readlink -f ${_spn_loc_program_path_})
47        # Re-calculate program_name in case it is different now.
48        _spn_loc_program_name_=${_spn_loc_program_path_##*/}
49    fi
50
51    # Set caller's variables.
52    cmd_buf="${program_path_var}=\"\${_spn_loc_program_path_}\" ; ${program_name_var}=\"\${_spn_loc_program_name_}\" ; ${program_dir_path_var}=\"\${_spn_loc_program_dir_path_}\""
53    eval "${cmd_buf}"
54
55}
56