Specifying -all will produce a summary line for each top-level folder in the user's nmh directory, sorted alphabetically. (If folder is invoked by a name ending with “s” (e.g. folders), -all is assumed). Specifying -recurse with -all will also produce a line for all sub-folders. These folders are all preceded by the read-only folders, which occur as “atr-cur-” entries in the user's nmh context. For example:

FOLDER	000000# MESSAGES	RANGE	CUR     (OTHERS)
/var/work/folder	has 035 messages	(01-035);	cur=23.
/usr/bugs/Mail	has 082 messages	(01-108);	cur=82.
ff	has 0no messages.
inbox+	has 016 messages	(03-022);	cur=05.
mh	has 076 messages	(15-076);	cur=70.
notes	has 002 messages	(01-002);	cur=01.
ucom	has 124 messages	(01-124);	cur=06; (others).

TOTAL = 339 messages in 7 folders

The “+” after inbox indicates that it is the current folder. The “(others)” indicates that the folder ucom has files which aren't messages. These files may either be sub-folders, or files that don't belong under the nmh file naming scheme.

The header is output if either a -all or a -header switch is specified. It is suppressed by -noheader.

The folder and message totals are output if either a -all or a -total switch is specified. It is suppressed by -nototal.

If -fast is given, only the folder name (or names in the case of -all) will be listed. (This is faster because the folders need not be read.)

If a +folder is given along with the -all switch, folder will, in addition to setting the current folder, list the top-level subfolders for the current folder (with -norecurse) or list all sub-folders under the current folder recursively (with -recurse). In this case, if a msg is also supplied, it will become the current message of +folder.

The -recurse switch lists each folder recursively, so use of this option effectively defeats the speed enhancement of the -fast option, since each folder must be searched for subfolders. Nevertheless, the combination of these options is useful.

The -pack switch will compress the message names in the designated folders, removing holes in message numbering. The -verbose switch directs folder to tell the user the general actions that it is taking to compress the folder.

The -push switch directs folder to push the current folder onto the folder-stack, and make the +folder argument the current folder. If +folder is not given, the current folder and the top of the folder-stack are exchanged. This corresponds to the “pushd” operation in the shell.

The -pop switch directs folder to discard the top of the folder-stack, after setting the current folder to that value. No +folder argument is allowed. This corresponds to the “popd” operation in the shell. The -push switch and the -pop switch are mutually exclusive: the last occurrence of either one overrides any previous occurrence of the other. Both of these switches also set -list by default.

The -list switch directs folder to list the contents of the folder-stack. No +folder argument is allowed. After a successful -push or -pop, the -list action is taken, unless a -nolist switch follows them on the command line. This corresponds to the “dirs” operation in the shell. The -push, -pop, and -list switches turn off -print.