Repeated Regex
When you want to make a search where a certain pattern repeats itself a number of times in a Regular Expression, make use of a repeated pattern:
| Meta-character | Description |
|---|---|
X* |
Match none or more repetitions of the Regular expression preceding it (X). |
X? |
Match none or one repetitions of the Regular expression preceding it (X). |
X+ |
Match one or more repetitions of the Regular expression preceding it (X). |
X{n} |
Match exactly (n) repetitions of the Regular expression (X). |
X{n,} |
Match (n) or more repetitions of X |
X{,n} |
Match zero or at max (n) repetitions of the Regular expression (X). |
X{n,m} |
Match with at least (n) repetitions of the RegEx (X) but max (m) repetitions. |
To use the extended Regular expressions, add the -E flag to the grep command:
grep --color -E '^[h-q]{8}$^ /usr/share/dict/spanish
homónimo
pimpollo
piojillo
piopollo