Node:Tilde Expansion, Next:Variable Substitution, Previous:Wordexp Example, Up:Word Expansion
It's a standard part of shell syntax that you can use ~ at the
beginning of a file name to stand for your own home directory. You
can use ~user to stand for user's home directory.
Tilde expansion is the process of converting these abbreviations to the directory names that they stand for.
Tilde expansion applies to the ~ plus all following characters up
to whitespace or a slash. It takes place only at the beginning of a
word, and only if none of the characters to be transformed is quoted in
any way.
Plain ~ uses the value of the environment variable HOME
as the proper home directory name. ~ followed by a user name
uses getpwname to look up that user in the user database, and
uses whatever directory is recorded there. Thus, ~ followed
by your own name can give different results from plain ~, if
the value of HOME is not really your home directory.