Nó trả về $line
với chuỗi con device name:
bị xóa. Từ trang bash man:
${parameter/pattern/string}
Pattern substitution. The pattern is expanded to produce a pattern just as in
pathname expansion. Parameter is expanded and the longest match of pattern against its value is replaced with string. If pattern begins with /, all
matches of pattern are replaced with string. Normally only the first match is
replaced. If pattern begins with #, it must match at the beginning of the
expanded value of parameter. If pattern begins with %, it must match at the
end of the expanded value of parameter. If string is null, matches of pattern are deleted and the/following pattern may be omitted. If parameter is @ or
*, the substitution operation is applied to each positional parameter in turn,
and the expansion is the resultant list. If parameter is an array variable
subscripted with @ or *, the substitution operation is applied to each member
of the array in turn, and the expansion is the resultant list.
Nguồn
2015-09-16 22:26:00
Cả hai câu trả lời là chính xác, nhưng đây là tài liệu về mở rộng tham số để tham khảo và chỉnh sửa sau này thành câu trả lời: http://www.gnu.org/software/bash/manual/html_node/ Shell-Parameter-Expansion.html –