In /usr/bin/src2man line 99:
shift $(($OPTIND - 1))
         ^-----^ SC2004: $/${} is unnecessary on arithmetic variables.


In /usr/bin/src2man line 129:
	grep_cmd = "test -f " inc " && grep -wq " title "  " inc " \
                                                                   ^-- SC1004: This backslash+linefeed is literal. Break outside single quotes if you just want to break the line.


In /usr/bin/src2man line 196:
	print "NAME\n" name (synop ? "\nSYNOPSIS\n  " synop : "") \
                                                                  ^-- SC1004: This backslash+linefeed is literal. Break outside single quotes if you just want to break the line.


In /usr/bin/src2man line 197:
	      "\nDESCRIPTION\n" desc "\nFILE\n  " FILENAME | \
                                                             ^-- SC1004: This backslash+linefeed is literal. Break outside single quotes if you just want to break the line.


In /usr/bin/src2man line 198:
	      "{ echo '\''.\\\" Extracted by src2man from " FILENAME "'\''; \
                                                                            ^-- SC1004: This backslash+linefeed is literal. Break outside single quotes if you just want to break the line.


In /usr/bin/src2man line 199:
	      txt2man -d \"$date\" -v \"" volume "\" -r " release \
                                                                  ^-- SC1004: This backslash+linefeed is literal. Break outside single quotes if you just want to break the line.


In /usr/bin/src2man line 203:
' $*
  ^-- SC2048: Use "$@" (with quotes) to prevent whitespace problems.
  ^-- SC2086: Double quote to prevent globbing and word splitting.

Did you mean: 
' "$*"

For more information:
  https://www.shellcheck.net/wiki/SC2048 -- Use "$@" (with quotes) to prevent...
  https://www.shellcheck.net/wiki/SC1004 -- This backslash+linefeed is litera...
  https://www.shellcheck.net/wiki/SC2086 -- Double quote to prevent globbing ...