gts-modifier
^[(+|-)n] $[(+|-)m] ^[(+|-)n]..$[(+|-)m] ^[(+|-)n]..^[(+|-)m] $[(+|-)n]..$[(+|-)m]
gts-modifiers are patterns for modifying locations within a sequence. A
modifier can take one of five forms: ^[(+|-)n], $[[(+|-)m]],
^[(+|-)n]..$[(+|-)m], ^[(+|-)n]..^[(+|-)m], or $[(+|-)n]..$[(+|-)m].
A caret ^ character denotes the beginning of the location and a dollar $
character denotes the end of the location. The numbers following these
characters denote the offset of the position, where a negative number
represents the 5' region and a positive number represents the 3' region. The
first two forms of the modifier will return a singular point location and the
latter three forms will return a modified range location. The positions and
offset values will be flipped for complement locations.
Collapse the location to the start of the region:
^
Collapse the location to the end of the region:
$
Leave the entire region as is:
^..$
Extend the region 20 bases upstream:
^-20..$
Focus the 20 bases around the end of the region:
$-20..$+20
gts(1), gts-extract(1), gts-locator(7)