File name abbreviation in the C shell

The tilde (~) and { characters indicate file name abbreviation. A ~ at the beginning of a file name is used to represent home directories. Standing alone, the ~ character expands to your home directory as reflected in the value of the home shell variable.

For example, the following command:
ls ~
lists all files and directories located in your $HOME directory.
When the command is followed by a name consisting of letters, digits, and hyphen (-) characters, the shell searches for a user with that name and substitutes that user's $HOME directory.
Note: If the ~ character is followed by a character other than a letter or slash (/), or appears anywhere except at the beginning of a word, it does not expand.
To match characters in file names without typing the entire file name, use { } around the file names. The pattern a{b,c,d}e is another way of writing abe ace ade. The shell preserves the left-to-right order and separately stores the results of matches at a low level to preserve this order. This construct might be nested. Thus, the following:
expands to:
/usr/source/s1/oldls.c /usr/source/s1/ls.c
if the home directory for source is /usr/source. Similarly, the following:
might expand to:
../memo ../box ../mbox
Note: memo is not sorted with the results of matching *box. As a special case, the {, }, and { } characters are passed undisturbed.