Comment lines in the Bourne shell

[lee at eel.UUCP]

The ":" character in the Bourne shell names the null command; it is not a
comment character.  The comment character is "#" (I understand that some
versions of the Bourne shell did not have this implemented). The difference
is that after the "#", no characters are interpreted, whereas after the ":"
all characters are interpreted as they would be for any command (including,
for example, commands in "`" characters so that the side-effects of embedded
commands will occur).