AWK can do this with pattern ranges, which allows the use of any regular expression:
echoer | awk '/pattern/,0'
echoer’s output starting with the first line matching
AWK is pattern-based, and is typically used with a “if this pattern matches, do this” type of approach. “This pattern” can be a range of patterns, defined as “when this pattern matches, start doing this, until this other pattern matches”; this is specified by writing two patterns separated by a comma, as above. Patterns can be text matches, as in
/pattern/, where the current line is checked against the pattern, interpreted as a regular expression; they can also be general expressions, evaluated for every line, and considered to match if their result is non-zero or non-empty.
In AWK, the default action is to print the current line.
Putting all this together,
awk '/pattern/,0' looks for lines matching
pattern, and once it finds one, applies the default action to all lines until the
0 condition matches (is non-zero).
awk '/pattern/,""' would work too.
The Gawk manual goes into much more detail.