gzip, bzip2: add -n flag to suppress modification timestamp

[plan9front.git] / sys / man / 1 / gzip

diff --git a/sys/man/1/gzip b/sys/man/1/gzip
index f56a6a2466a6e882a5d4f7ec6f2209c966786d28..12288e8bb45940e972c4158c171d8354dade0679 100644 (file)
--- a/sys/man/1/gzip
+++ b/sys/man/1/gzip
@@ -3,7 +3,7 @@
 gzip, gunzip, bzip2, bunzip2, compress, uncompress, zip, unzip \- compress and expand data
 .SH SYNOPSIS
 .B gzip
-.RB [ -cvD [ 1-9 ]]
+.RB [ -cvnD [ 1-9 ]]
 .RI [ file
 .BR ... ]
 .PP
@@ -13,7 +13,7 @@ gzip, gunzip, bzip2, bunzip2, compress, uncompress, zip, unzip \- compress and e
 .BR ... ]
 .PP
 .B bzip2
-.RB [ -cvD [ 1-9 ]]
+.RB [ -cvnD [ 1-9 ]]
 .RI [ file
 .BR ... ]
 .PP
@@ -180,6 +180,19 @@ Without
 .BR -t ,
 prints the names of files on standard error as they are compressed or decompressed.
 .TP
+.B -n
+The
+.I gzip
+and
+.I bzip2
+file formats include a modification timestamp which is by default set
+to the modification time of the files being compressed or the current
+time when the source file is read from standard input.
+The
+.B -n
+flag overrides this behaviour and puts a timestamp of zero instead,
+making the compressed output deterministic.
+.TP
 .B -D
 Produce debugging output.
 .SH SOURCE