Enhanced man page text for options -chmod, -chown, -chgrp

test/xorriso.1

@@ -313,13 +313,29 @@ Rename the given file objects in the ISO tree to the last
 argument in the list. Use the same rules as with shell command mv.
 .TP
 \fB\-chown\fR uid iso_rr_path [...]
-Equivalent to shell command chown in the ISO image.
+Set ownership of file objects in the ISO image. uid may either be a decimal
+number or the name of a user known to the operating system.
 .TP
 \fB\-chgrp\fR gid iso_rr_path [...]
-Equivalent to shell command chgrp in the ISO image.
+Set group attribute of file objects in the ISO image. gid  may either be a
+decimal number or the name of a group known to the operating system.
 .TP
 \fB\-chmod\fR mode iso_rr_path [...]
-Equivalent to shell command chmod in the ISO image.  
+Equivalent to shell command chmod in the ISO image.
+mode is either an octal number beginning with "0" or a comma separated
+list of statements of the form [ugoa]*[+-=][rwxst]* . Like: go-rwx,u+rwx .
+.br
+.B Personalities:
+u=user, g=group, o=others, a=all
+.br
+.B Operators:
++ adds given permissions, - revokes given permissions,
+= revokes all old permissions and then adds the given ones.
+.br
+.B Permissions:
+r=read, w=write, x=execute|inspect, s=setuid|setgid, t=sticky bit
+.br
+For octal numbers see man 2 stat.
 .TP
 \fB\-alter_date\fR type timestring iso_rr_path [...]
 Alter the date entries of a file in the ISO image. type is