Linux Admin 3: regular expressions 1

grep, awk, sed & perl all use REs
different from filename wildcards
matches the pattern anywhere in a line
group work: match he out of: the he she hpe fiend
character meaning

^ match pattern at beginning of line

$ match preceding pattern at end of line

. match any single character
* match ZERO or more repetitions of previous char
^a will match all lines that begin with a
fred$ will match all lines that end with 'fred'
.he will match she, the, che, or any other 3-letter word that has 'he' as the second and 3rd characters.
t* will match t, tt, tttttttttt, or any number of t's: Including NONE!

character	meaning
^	match pattern at beginning of line
$	match preceding pattern at end of line
.	match any single character
*	match ZERO or more repetitions of previous char