www.delorie.com/gnu/docs/tar/tar_33.html

search

	Buy GNU books!

GNU tar

3.3.1 Mnemonic Option Style

@quote-arg {have to decide whether or ot to replace other occurrences of "mnemonic" with "long", or *ugh* vice versa.}

Each option has at least one long (or mnemonic) name starting with two dashes in a row, e.g. `list'. The long names are more clear than their corresponding short or old names. It sometimes happens that a single mnemonic option has many different different names which are synonymous, such as `--compare' and `--diff'. In addition, long option names can be given unique abbreviations. For example, `--cre' can be used in place of `--create' because there is no other mnemonic option which begins with `cre'. (One way to find this out is by trying it and seeing what happens; if a particular abbreviation could represent more than one option, tar will tell you that that abbreviation is ambiguous and you'll know that that abbreviation won't work. You may also choose to run `tar --help' to see a list of options. Be aware that if you run tar with a unique abbreviation for the long name of an option you didn't want to use, you are stuck; tar will perform the command as ordered.)

Mnemonic options are meant to be obvious and easy to remember, and their meanings are generally easier to discern than those of their corresponding short options (see below). For example:

$ tar --create --verbose --blocking-factor=20 --file=/dev/rmt0

gives a fairly good set of hints about what the command does, even for those not fully acquainted with tar.

Mnemonic options which require arguments take those arguments immediately following the option name; they are introduced by an equal sign. For example, the `--file' option (which tells the name of the tar archive) is given a file such as `archive.tar' as argument by using the notation `--file=archive.tar' for the mnemonic option.