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This question has good answers for synopsis syntax but doesn't have any info on curly brackets '{}': Understand synopsis in manpage

Example in the tar man page

NAME

 tar -- manipulate tape archives

SYNOPSIS

 tar [bundled-flags <args>] [<file> | <pattern> ...]
 tar {-c} [options] [files | directories]
 tar {-r | -u} -f archive-file [options] [files | directories]
 tar {-t | -x} [options] [patterns]

I think the curly brackets mean 'if you use these options in the curly brackets then this is the format for the usage'. Can anyone confirm?

Douglas Young
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1 Answers1

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Ah, I just re-read the description and I believe my assumption is correct, that those are the specific usages for those options that differ to each other:

The first synopsis form shows a ``bundled'' option word

The other synopsis forms show the preferred usage

DESCRIPTION
     tar creates and manipulates streaming archive files.  This implementation can extract from tar, pax, cpio, zip, jar, ar, xar, rpm, 7-zip,
     and ISO 9660 cdrom images and can create tar, pax, cpio, ar, zip, 7-zip, and shar archives.

 The first synopsis form shows a ``bundled'' option word.  This usage is provided for compatibility with historical implementations.  See
 COMPATIBILITY below for details.

 The other synopsis forms show the preferred usage.  The first option to tar is a mode indicator from the following list:
 -c      Create a new archive containing the specified items.  The long option form is --create.
 -r      Like -c, but new entries are appended to the archive.  Note that this only works on uncompressed archives stored in regular files.
         The -f option is required.  The long option form is --append.
 -t      List archive contents to stdout.  The long option form is --list.
 -u      Like -r, but new entries are added only if they have a modification date newer than the corresponding entry in the archive.  Note
         that this only works on uncompressed archives stored in regular files.  The -f option is required.  The long form is --update.
 -x      Extract to disk from the archive.  If a file with the same name appears more than once in the archive, each copy will be extracted,
         with later copies overwriting (replacing) earlier copies.  The long option form is --extract.

 In -c, -r, or -u mode, each specified file or directory is added to the archive in the order specified on the command line.  By default,
 the contents of each directory are also archived.

 In extract or list mode, the entire command line is read and parsed before the archive is opened.  The pathnames or patterns on the command
 line indicate which items in the archive should be processed.  Patterns are shell-style globbing patterns as documented in tcsh(1).
Douglas Young
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