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Diffstat (limited to 'doc')
| -rw-r--r-- | doc/coreutils.texi | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/doc/coreutils.texi b/doc/coreutils.texi index ae3712dba..8dd1ed8ba 100644 --- a/doc/coreutils.texi +++ b/doc/coreutils.texi @@ -8174,6 +8174,31 @@ last-access and last-modified time) is not necessarily synchronized. @cindex synchronized data and metadata I/O Use synchronized I/O for both data and metadata. +@item nocache +@opindex nocache +@cindex discarding file cache +Discard the data cache for a file. +When count=0 all cache is discarded, +otherwise the cache is dropped for the processed +portion of the file. Also when count=0 +failure to discard the cache is diagnosed +and reflected in the exit status. +Here as some usage examples: + +@example +# Advise to drop cache for whole file +dd if=ifile iflag=nocache count=0 + +# Ensure drop cache for the whole file +dd of=ofile oflag=nocache conv=notrunc,fdatasync count=0 + +# Drop cache for part of file +dd if=ifile iflag=nocache skip=10 count=10 of=/dev/null + +# Stream data using just the read-ahead cache +dd if=ifile of=ofile iflag=nocache oflag=nocache +@end example + @item nonblock @opindex nonblock @cindex nonblocking I/O |