Fine tuning of --outprefix

The standard separator after $FNAME_PREFIX is now '-'.
You can as well supply a different <fname_prefix> ending in '.',  '_' or ',' , then
no no additional '-' will be appended.

Also a small bash function get_last_char() has been introduced which returns
the last char from a supplied string.

doc/testssl.1

@@ -412,7 +412,7 @@ whole 9 yards
 \fB\-\-append\fR Normally, if an output file already exists and it has a file size greater zero, testssl\.sh will prompt you to manually remove the file exit with an error\. \fB\-\-append\fR however will append to this file, without a header\. The environment variable APPEND does the same\. Be careful using this switch/variable\. A complementary option which overwrites an existing file doesn\'t exist per design\.
 .
 .P
-\fB\-\-outprefix <fname_prefix>\fR Prepend output filename prefix \fIfname_prefix\fR before \'\e${NODE}\.\'\. You can use as well the environment variable FNAME_PREFIX\. Using this any output files will be named \fB<fname_prefix>\.${NODE}\-p${port}${YYYYMMDD\-HHMM}\.<format>\fR when no file name of the respective output option was specified\.
+\fB\-\-outprefix <fname_prefix>\fR Prepend output filename prefix \fIfname_prefix\fR before \'\e${NODE}\-\'\. You can use as well the environment variable FNAME_PREFIX\. Using this any output files will be named \fB<fname_prefix>\-${NODE}\-p${port}${YYYYMMDD\-HHMM}\.<format>\fR when no file name of the respective output option was specified\. If you do not like the separator \'\-\' you can as well supply a \fB<fname_prefix>\fR ending in \'\.\', \'_\' or \',\'\. In this case or if you already supplied \'\-\' no additional \'\-\' will be appended to \fB<fname_prefix>\fR\.
 .
 .P
 A few file output options can also be preset via environment variables\.

doc/testssl.1.html

@@ -394,7 +394,7 @@ The same can be achieved by setting the environment variable <code>WARNINGS</cod
 
 <p><code>--append</code>                      Normally, if an output file already exists and it has a file size greater zero, testssl.sh will prompt you to manually remove the file exit with an error. <code>--append</code> however will append to this file, without a header. The environment variable APPEND does the same. Be careful using this switch/variable. A complementary option which overwrites an existing file doesn't exist per design.</p>
 
-<p><code>--outprefix &lt;fname_prefix></code>   Prepend output filename prefix <var>fname_prefix</var> before '\${NODE}.'. You can use as well the environment variable FNAME_PREFIX. Using this any output files will be named <code>&lt;fname_prefix>.${NODE}-p${port}${YYYYMMDD-HHMM}.&lt;format></code> when no file name of the respective output option was specified.</p>
+<p><code>--outprefix &lt;fname_prefix></code>   Prepend output filename prefix <var>fname_prefix</var> before '\${NODE}-'. You can use as well the environment variable FNAME_PREFIX. Using this any output files will be named <code>&lt;fname_prefix>-${NODE}-p${port}${YYYYMMDD-HHMM}.&lt;format></code> when no file name of the respective output option was specified. If you do not like the separator '-' you can as well supply a <code>&lt;fname_prefix></code> ending in '.',  '_' or ','. In this case or if you already supplied '-' no additional '-' will be appended to <code>&lt;fname_prefix></code>.</p>
 
 <p>A few file output options can also be preset via environment variables.</p>
 

doc/testssl.1.md

@@ -316,7 +316,7 @@ The same can be achieved by setting the environment variable `WARNINGS`.
 
 `--append`                      Normally, if an output file already exists and it has a file size greater zero, testssl.sh will prompt you to manually remove the file exit with an error. `--append` however will append to this file, without a header. The environment variable APPEND does the same. Be careful using this switch/variable. A complementary option which overwrites an existing file doesn't exist per design.
 
-`--outprefix <fname_prefix>`   Prepend output filename prefix <fname_prefix> before '\${NODE}.'. You can use as well the environment variable FNAME_PREFIX. Using this any output files will be named `<fname_prefix>.${NODE}-p${port}${YYYYMMDD-HHMM}.<format>` when no file name of the respective output option was specified.
+`--outprefix <fname_prefix>`   Prepend output filename prefix <fname_prefix> before '\${NODE}-'. You can use as well the environment variable FNAME_PREFIX. Using this any output files will be named `<fname_prefix>-${NODE}-p${port}${YYYYMMDD-HHMM}.<format>` when no file name of the respective output option was specified. If you do not like the separator '-' you can as well supply a `<fname_prefix>` ending in '.',  '_' or ','. In this case or if you already supplied '-' no additional '-' will be appended to `<fname_prefix>`.
 
 A few file output options can also be preset via environment variables.