The simplest character set is a single
character. The regular expression the contains
three character sets: t, h, and
e. It will match any line that contains the string
the, including the word other.
To prevent this, put spaces () before
and after the pattern:
the
.
You can combine the
string with an anchor. The pattern
^From: will match
the lines of a mail message (Section 1.21) that identify the sender. Use this pattern
with grep to print every address in your incoming
mailbox. [If your system doesn't define the
environment variable MAIL, try
/var/spool/mail/$USER or possibly
/usr/spool/mail/$USER.
-- SJC]
$USER Section 35.5
% grep '^From: ' $MAIL
Some characters have a special meaning in regular expressions. If you want to search for such a character as itself, escape it with a backslash (\).
-- BB
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