DSGREP(1)

NAME
dsgrep - Search discuss meetings with regular expressions

SYNOPSIS
dsgrep [-n n_trans] [-e search_regexp] [-f meetings_file] [-t trans_num] [-a] [-p] [-v] [-i] [meetingname1 meetingname2 ...]

DESCRIPTION
Dsgrep searches discuss meetings for transactions that have titles that match the given regular expression, or have contents that match the regular expression. The title of the matching transactions or their contents can be printed. Dsgrep understands the following options:

-n n_trans
    specifies the number of transactions to look back from the last transaction in each discuss meeting specified. This defaults to 50. This option is ignored when the -t option is specified.

-e search_regexp
    This specifies the regular expression to be matched, in the style of egrep(1). A detailed explaination of the regular expression format is given below. If this is omitted, it defaults to "*", matching all transactions.

-f meetings_file
    This specifies an alternative meetings file to use as a source of meetings. If this option is not specified, it will use the file ${HOME}/.meetings.,

-t trans_num
    Print out a specific transaction, by number. When this option is used, the -n option is ignored.

-a  Causes dsgrep to search the text of the transactions for the regular expressions as well as their titles.

-p  Causes the text of the text of the matching transactions to be printed instead of just the title.

-v  Causes errors getting transactions to be reported. These errors are usually due to deleted transactions in the meetings, and are ususally not worth seeing.

-d  Causes deleted transactions to be searched as well. Otherwise, deleted transactions are ignored.

-i  Ignores case when matching against search_regexp.

meetings
    This specifies the meetings to search; if it is left off, dsgrep will search all the meetings.

REGULAR EXPRESSION SYNTAX
A regular expression is zero or more branches, separated by `|'. It matches anything that matches one of the branches.

A branch is zero or more pieces, concatenated. It matches a match for the first, followed by a match for the second, etc.

A piece is an atom possibly followed by `*', `+', or `?'. An atom followed by `*' matches a sequence of 0 or more matches of the atom. An atom followed by `+' matches a sequence of 1 or more matches of the atom. An atom followed by `?' matches a match of the atom, or the null string.

An atom is a regular expression in parentheses (matching a match for the regular expression), a range (see below), `.' (matching any single character), `^' (matching the null string at the beginning of the input string), `$' (matching the null string at the end of the input string), a `\' followed by a single character (matching that character), or a single character with no other significance (matching that character).

A range is a sequence of characters enclosed in `[]'. It normally matches any single character from the sequence. If the sequence begins with `^', it matches any single character not from the rest of the sequence. If two characters in the sequence are separated by `-', this is shorthand for the full list of ASCII characters between them (e.g. `[0-9]' matches any decimal digit). To include a literal `]' in the sequence, make it the first character (following a possible `^'). To include a literal `-', make it the first or last character.

AMBIGUITY
If a regular expression could match two different parts of the input string, it will match the one which begins earliest.
If both begin in the same place    but match different lengths, or match
the same length in different ways, life gets messier, as follows.

In general, the possibilities in a list of branches are considered in left-to-right order, the possibilities for `*', `+', and `?' are considered longest-first, nested constructs are considered from the outermost in, and concatenated constructs are considered leftmost-first. The match that will be chosen is the one that uses the earliest possibility in the first choice that has to be made. If there is more than one choice, the next will be made in the same manner (earliest possibility) subject to the decision on the first choice. And so forth.

For example, `(ab|a)b*c' could match `abc' in one of two ways. The first choice is between `ab' and `a'; since `ab' is earlier, and does lead to a successful overall match, it is chosen. Since the `b' is already spoken for, the `b*' must match its last possibility—the empty string—since it must respect the earlier choice.

In the particular case where no `|'s are present and there is only one `*', `+', or `?', the net effect is that the longest possible match will be chosen. So `ab*', presented with `xabbbby', will match `abbbb'. Note that if `ab*' is tried against `xabyabbbz', it will match `ab' just after `x', due to the begins-earliest rule. (In effect, the decision on where to start the match is the first choice to be made, hence subsequent choices must respect it even if this leads them to less-preferred alternatives.)

SEE ALSO

egrep(1), discuss(1)