bsdtar的-q選項

Question

我在bash腳本中運行了以下代碼。

# See if bsdtar can recognize the file 
if bsdtar -tf "$file" -q '*' &>/dev/null; then 
    cmd="bsdtar" 
else 
continue 

'-q'選項的含義是什麼？我在bsdtar命令的幫助信息中找不到任何信息。

謝謝！

Answer 1

從的bsdtar man page：

-q (--fast-read) 
    (x and t mode only) Extract or list only the first archive entry 
    that matches each pattern or filename operand. Exit as soon as 
    each specified pattern or filename has been matched. By default, 
    the archive is always read to the very end, since there can be 
    multiple entries with the same name and, by convention, later 
    entries overwrite earlier entries. This option is provided as a 
    performance optimization.