man/man1/ln.1

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NAME            ln  --  make a link
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SYNOPSIS        ln\b\b__ name\d1\u [ name\d2\u ]
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DESCRIPTION     ln\b\b__ creates a link to an existing file name\d1\u.
If name\d2\u is given, the link has that name;
otherwise it is placed in the current directory
and its name is the last component
of name\d1\u.
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It is forbidden to link to a directory
or to link across file systems.
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FILES           --
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SEE ALSO        rm(I)
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DIAGNOSTICS     "?"
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BUGS            There is nothing particularly
wrong with ln\b\b__, but links don't work right with respect
to the backup system:  one copy is backed up for each link, and
(more serious) in case of a file system reload
both copies are restored and the information that a link was involved
is lost.