#6 UNIX Shebang functionality

[Bill Chatfield]

I'd like to be able to make scripts executable on UNIX-like systems by having the first line of the script include the interpreter, in the UNIX tradition:

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#!/usr/bin/bwbasic FOR I = 1 TO 10 PRINT I NEXT I

This is called "shebang" or "hashbang". https://en.wikipedia.org/wiki/Shebang_(Unix)

The script also has to be made executable: chmod a+x <script-name>

This feature allows you to run the script by just typing its name rathar than having to type "bwbasic <script-name>. But, it not just that convenience, this feature also allows you to put scripts in a directory in your PATH and find them without having to type their full path name. I general, it would allow bwbasic scripts to be run just like any other UNIX command, making them a first class citizen of the system.

Currently the "#" on the first line causes an error with bwbasic. Making this work will require adding a special case in the code just for the "#" on the first line.

[Bill Chatfield]

The correct link is: Shebang

[AF5NE]

This functionality has been added to bwBASIC 3.30.. Here is the fix for bwb_fload() in bwbasic.c:

    My->NextValidLineNumber = MINLIN;
    while (fgets (tbuf, tlen, file))        /* bwb_fload */
    {
      tbuf[tlen] = NulChar;
      CleanLine (tbuf);
      if (is_empty_string (tbuf))
      {
        /* ignore */
+     }
+     else if (tbuf[0] == '#' && tbuf[1] == '!')
+     {
+       /* #!/usr/bin/bwbasic */
      }
      else if (bwb_strnicmp (tbuf, Magic_Word, Magic_Length) == 0)

[Daniel D. Rodrigues]

Hey Howard, can you share the code for bwbasic 3.30? Also, FYI, I have created a GitHub repository: https://github.com/nerun/bwbasic. If you want access, let me know.

[AF5NE]

Here is the testcase (SHEBANG1.BAS) added to bwBASIC 3.30:

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#!/usr/bin/bwbasic 100 REM ------------------------------------------------------------ 110 REM PURPOSE: VERIFY SHEBANG (#!) IS A COMMENT 120 REM AUTHOR: HOWARD WULF, AF5NE 130 REM DATE: 2019-07-01 140 REM FILENAME: SHEBANG1.BAS 150 REM 200 FOR I = 1 TO 10 210 PRINT I 220 NEXT I 999 PRINT "TEST PASSED"

[Bill Chatfield]

Thanks! You rock! Now I just have to find out why Fedora is still shipping bwBASIC 3.20.

[Bill Chatfield]

I guess you could close the ticket now.

[Paul Edwards]

I think we need to wait for bwBASIC 3.30 to actually be released. I don't have all the code from Howard yet.

[Bill Chatfield]

Oh. I see. I didn't realize it was still in progress.