grep¶

print lines matching a regular expression
NAME
    grep - print lines matching a regular expression

SYNOPSIS
    grep pattern [file]
    grep -r pattern

DESCRIPTION
    Prints the lines of a file (or of standard input) that match a basic
    regular expression. grep is a /bin program.

    The regex dialect:
        .        any single character
        *  +  ?  zero-or-more / one-or-more / zero-or-one of the
                 preceding character
        ^        anchor to the start of the line (special only first)
        $        anchor to the end of the line   (special only last)
    Everything else is a literal. There are no character classes or
    alternation yet.

OPTIONS
    -r    recurse the CWD tree, grepping every file

LIMITS
    With -r, walks at most 8 levels below the CWD and collects at most
    36 files; deeper or larger trees are searched only in part, with no
    warning. The regex is capped at 63 characters and lines at 175.

EXAMPLES
    grep "^al" FILE          lines starting with "al"
    grep "be.a" <FILE        be, any char, a  (from a redirect)
    cmd | grep "x.*y"        filter a pipe
    grep -r alpha            search every file under the CWD

SEE ALSO
    sed, find, cat