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diff --git a/man/1/sh-regex b/man/1/sh-regex new file mode 100644 index 00000000..9fe4f820 --- /dev/null +++ b/man/1/sh-regex @@ -0,0 +1,178 @@ +.TH SH-REGEX 1 +.SH NAME +re, match \- shell script regular expression handling +.SH SYNOPSIS +.B load regex + +.B match +.I regex +[ +.IR arg ... +] +.br +.B ${re +.I op +.IR arg... +.B } +.br +.SH DESCRIPTION +.I Regex +is a loadable module for +.IR sh (1) +that provides access to regular-expression +pattern matching and substitution. +For details of regular expression syntax in Inferno, +see +.IR regexp (6). +.I Regex +defines one builtin command, +.BR match , +and one builtin substitution operator, +.BR re . +.B Match +gives a false exit status if its argument +.I regex +fails to match any +.IR arg . +.B Re +provides several operations, detailed below: +.TP 10 +\f5${re g\fP \fIregexp\fP \fR[\fP \fIarg\fP\fR...\fP\fR]\fP\f5}\fP +Yields a list of each +.I arg +that matches +.IR regexp . +.TP +\f5${re v\fP \fIregexp\fP \fR[\fP \fIarg\fP\fR...\fP\fR]\fP\f5}\fP +Yields a list of each +.I arg +that does not match +.IR regexp . +.TP +\f5${re m\fP \fIregexp\fP \fIarg\fP\f5}\fP +Yields the portion of +.I arg +that matches +.IR regexp , +or an empty list if there was no match. +.TP +\f5${re M\fP \fIregexp\fP \fIarg\fP\f5}\fP +Yields a list consisting of the portion +of +.I arg +that matches +.IR regexp , +followed by list elements giving the portion +of +.I arg +that matched each parenthesized subexpression +in turn. +.TP +\f5${re mg\fP \fIregexp\fP \fIarg\fP\f5}\fP +Similar to +.B re m +except that it applies the match consecutively +through +.IR arg , +yielding a list of all the portions of +.I arg +that match +.IR regexp . +If a match is made to the null string, +no subsequent substitutions will take place. +.TP +\f5${re s\fP \fIregexp\fP \fIsubs\fP [ \fIarg\fP... ]\f5}\fP +For each +.IR arg , +.B re s +substitutes the first occurrence of +.I regexp +(if any) by +.IR subs . +If +.I subs +contains a sequence of the form +.BI \e d +where +.I d +is a single decimal digit, +the +.IR d th +parenthesised subexpression in +.I regexp +will be substituted in its place. +.B \e0 +is substituted by the entire match. +If any other character follows a +backslash +.RB ( \e ), +that character will be substituted. +Arguments which contain no match to +.I regexp +will be left unchanged. +.TP +\f5${re sg\fP \fIregexp\fP \fIsubs\fP [ \fIarg\fP... ]\f5}\fP +Similar to +.B re s +except that all matches of +.I regexp +within each +.I arg +will be substituted for, rather than just the +first match. Only one occurrence of the null string is +substituted. +.PP +.SH EXAMPLES +List all files in the current directory that +end in +.B .dis +or +.BR .sbl : +.EX + ls -l ${re g '\e.(sbl|dis)$' *} +.EE +.PP +Break +.I string +up into its constituent characters, +putting the result in shell variable +.BR x : +.EX + x = ${re mg '.|\en' \fIstring\fP} +.EE +.PP +Quote a string +.B s +so that it can be used as +a literal regular expression without worrying +about metacharacters: +.EX + s = ${re sg '[*|[\e\e+.^$()?]' '\e\e\e0' $s} +.EE +.PP +Define a substitution function +.B pat2regexp +to convert shell-style +patterns into equivalent regular expressions +(e.g. +.RB `` ?.sbl* '' +would become +.RB `` ^.\e.sbl.*$ ''): +.EX + load std + subfn pat2regexp { + result = '^' ^ ${re sg '\e*' '.*' + ${re sg '\?' '.' + ${re sg '[()+\e\e.^$|]' '\e\e\e0' $*} + } + } ^ '$' + } +.EE +.SH SOURCE +.B /appl/cmd/sh/regex.b +.SH SEE ALSO +.IR regexp (6), +.IR regex (2), +.IR sh (1), +.IR string (2), +.IR sh-std (1) |