tar: simplify extraction examples (#3336)

Dropped the examples for extraction of specific compressed archives, tar
has had autodetection of the compression for over two decades.

Removed the dashes. No versions of tar require them and all they do is
cost you POSIX compatibility. (POSIX tar did *not* allow for the
dashes.)

pages/common/tar.md

@@ -6,32 +6,28 @@
 
 - Create an archive from files:
 
-`tar -cf {{target.tar}} {{file1 file2 file3}}`
+`tar cf {{target.tar}} {{file1 file2 file3}}`
 
 - Create a gzipped archive:
 
-`tar -czf {{target.tar.gz}} {{file1 file2 file3}}`
+`tar czf {{target.tar.gz}} {{file1 file2 file3}}`
 
-- Extract an archive in a target directory:
+- Extract a (compressed) archive into the current directory:
 
-`tar -xf {{source.tar}} -C {{directory}}`
+`tar xf {{source.tar[.gz|.bz2|.xz]}}`
 
-- Extract a gzipped archive in the current directory:
+- Extract an archive into a target directory:
 
-`tar -xzf {{source.tar.gz}}`
-
-- Extract a bzipped archive in the current directory:
-
-`tar -xjf {{source.tar.bz2}}`
+`tar xf {{source.tar}} -C {{directory}}`
 
 - Create a compressed archive, using archive suffix to determine the compression program:
 
-`tar -caf {{target.tar.xz}} {{file1 file2 file3}}`
+`tar caf {{target.tar.xz}} {{file1 file2 file3}}`
 
 - List the contents of a tar file:
 
-`tar -tvf {{source.tar}}`
+`tar tvf {{source.tar}}`
 
 - Extract files matching a pattern:
 
-`tar -xf {{source.tar}} --wildcards {{"*.html"}}`
+`tar xf {{source.tar}} --wildcards {{"*.html"}}`