diff options
| -rw-r--r-- | toys/posix/sed.c | 179 |
1 files changed, 64 insertions, 115 deletions
diff --git a/toys/posix/sed.c b/toys/posix/sed.c index 0896959f..c51585a6 100644 --- a/toys/posix/sed.c +++ b/toys/posix/sed.c @@ -10,6 +10,12 @@ * TODO: handle error return from emit(), error_msg/exit consistently * What's the right thing to do for -i when write fails? Skip to next? * test '//q' with no previous regex, also repeat previous regex? + * + * Deviations from POSIX: allow extended regular expressions with -r, + * editing in place with -i, separate with -s, NUL-separated input with -z, + * printf escapes in text, line continuations, semicolons after all commands, + * 2-address anywhere an address is allowed, "T" command, multiline + * continuations for [abc], \; to end [abc] argument before end of line. USE_SED(NEWTOY(sed, "(help)(version)e*f*i:;nErz(null-data)[+Er]", TOYFLAG_BIN|TOYFLAG_LOCALE|TOYFLAG_NOHELP)) @@ -19,8 +25,7 @@ config SED help usage: sed [-inrzE] [-e SCRIPT]...|SCRIPT [-f SCRIPT_FILE]... [FILE...] - Stream editor. Apply one or more editing SCRIPTs to each line of input - (from FILE or stdin) producing output (by default to stdout). + Stream editor. Apply editing SCRIPTs to lines of input. -e Add SCRIPT to list -f Add contents of SCRIPT_FILE to list @@ -29,144 +34,88 @@ config SED -r Use extended regular expression syntax -E POSIX alias for -r -s Treat input files separately (implied by -i) - -z Use \0 rather than \n as the input line separator + -z Use \0 rather than \n as input line separator - A SCRIPT is a series of one or more COMMANDs separated by newlines or - semicolons. All -e SCRIPTs are concatenated together as if separated - by newlines, followed by all lines from -f SCRIPT_FILEs, in order. - If no -e or -f SCRIPTs are specified, the first argument is the SCRIPT. + A SCRIPT is one or more COMMANDs separated by newlines or semicolons. + All -e SCRIPTs are combined as if separated by newlines, followed by all -f + SCRIPT_FILEs. If no -e or -f then first argument is the SCRIPT. - Each COMMAND may be preceded by an address which limits the command to - apply only to the specified line(s). Commands without an address apply to - every line. Addresses are of the form: + COMMANDs apply to every line unless prefixed with an ADDRESS of the form: [ADDRESS[,ADDRESS]][!]COMMAND - The ADDRESS may be a decimal line number (starting at 1), a /regular - expression/ within a pair of forward slashes, or the character "$" which - matches the last line of input. (In -s or -i mode this matches the last - line of each file, otherwise just the last line of the last file.) A single - address matches one line, a pair of comma separated addresses match - everything from the first address to the second address (inclusive). If - both addresses are regular expressions, more than one range of lines in - each file can match. The second address can be +N to end N lines later. - - REGULAR EXPRESSIONS in sed are started and ended by the same character - (traditionally / but anything except a backslash or a newline works). - Backslashes may be used to escape the delimiter if it occurs in the - regex, and for the usual printf escapes (\abcefnrtv and octal, hex, - and unicode). An empty regex repeats the previous one. ADDRESS regexes - (above) require the first delimiter to be escaped with a backslash when - it isn't a forward slash (to distinguish it from the COMMANDs below). - - Sed mostly operates on individual lines one at a time. It reads each line, - processes it, and either writes it to the output or discards it before - reading the next line. Sed can remember one additional line in a separate - buffer (using the h, H, g, G, and x commands), and can read the next line - of input early (using the n and N command), but other than that command - scripts operate on individual lines of text. - - Each COMMAND starts with a single character. The following commands take - no arguments: - - ! Run this command when the test _didn't_ match. - - { Start a new command block, continuing until a corresponding "}". - Command blocks may nest. If the block has an address, commands within - the block are only run for lines within the block's address range. - - } End command block (this command cannot have an address) + ADDRESS is a line number (starting at 1), a /REGULAR EXPRESSION/, or $ for + last line (-s or -i makes it last line of each file). One address matches one + line, ADDRESS,ADDRESS matches from first to second inclusive. Two regexes can + match multiple ranges. ADDRESS,+N ends N lines later. ! inverts the match. + + REGULAR EXPRESSIONS start and end with the same character (anything but + backslash or newline). To use the delimiter in the regex escape it with a + backslash, and printf escapes (\abcefnrtv and octal, hex, and unicode) work. + An empty regex repeats the previous one. ADDRESS regexes require any + first delimiter except / to be \escaped to distinguish it from COMMANDs. + + Sed reads each line of input, processes it, and writes it out or discards it + before reading the next. Sed can remember one additional line in a separate + buffer (the h, H, g, G, and x commands), and can read the next line of input + early (the n and N commands), but otherwise operates on individual lines. + + Each COMMAND starts with a single character. Commands with no arguments are: + ! Run this command when the ADDRESS _didn't_ match. + { Start new command block, continuing until a corresponding "}". + Command blocks nest and can have ADDRESSes applying to the whole block. + } End command block (this COMMAND cannot have an address) d Delete this line and move on to the next one (ignores remaining COMMANDs) - D Delete one line of input and restart command SCRIPT (same as "d" unless you've glued lines together with "N" or similar) - g Get remembered line (overwriting current line) - G Get remembered line (appending to current line) - h Remember this line (overwriting remembered line) - H Remember this line (appending to remembered line, if any) - - l Print line, escaping \abfrtv (but not newline), octal escaping other - nonprintable characters, wrapping lines to terminal width with a - backslash, and appending $ to actual end of line. - - n Print default output and read next line, replacing current line - (If no next line available, quit processing script) - - N Append next line of input to this line, separated by a newline - (This advances the line counter for address matching and "=", if no - next line available quit processing script without default output) - + l Print line escaping \abfrtv (but not \n), octal escape other nonprintng + chars, wrap lines to terminal width with \, append $ to end of line. + n Print default output and read next line over current line (quit at EOF) + N Append \n and next line of input to this line. Quit at EOF without + default output. Advances line counter for ADDRESS and "=". p Print this line - P Print this line up to first newline (from "N") - q Quit (print default output, no more commands processed or lines read) - x Exchange this line with remembered line (overwrite in both directions) - - = Print the current line number (followed by a newline) - - The following commands (may) take an argument. The "text" arguments (to - the "a", "b", and "c" commands) may end with an unescaped "\" to append - the next line (for which leading whitespace is not skipped), and also - treat ";" as a literal character (use "\;" instead). - - a [text] Append text to output before attempting to read next line - - b [label] Branch, jumps to :label (or with no label, to end of SCRIPT) - - c [text] Delete line, output text at end of matching address range - (ignores remaining COMMANDs) - - i [text] Print text - - r [file] Append contents of file to output before attempting to read - next line. - - s/S/R/F Search for regex S, replace matched text with R using flags F. - The first character after the "s" (anything but newline or - backslash) is the delimiter, escape with \ to use normally. - - The replacement text may contain "&" to substitute the matched - text (escape it with backslash for a literal &), or \1 through - \9 to substitute a parenthetical subexpression in the regex. - You can also use the normal backslash escapes such as \n and - a backslash at the end of the line appends the next line. - - The flags are: - - [0-9] A number, substitute only that occurrence of pattern - g Global, substitute all occurrences of pattern + = Print the current line number (plus newline) + # Comment, ignores rest of this line of SCRIPT (until newline) + + Commands that take an argument: + + : LABEL Target for jump commands + a TEXT Append text to output before reading next line + b LABEL Branch, jumps to :LABEL (with no LABEL to end of SCRIPT) + c TEXT Delete matching ADDRESS range and output TEXT instead + i TEXT Insert text (output immediately) + r FILE Append contents of FILIE to output before reading next line. + s/S/R/F Search for regex S replace match with R using flags F. Delimiter + is anything but \n or \, escape with \ to use in S or R. Printf + escapes work. Unescaped & in R becomes full matched text, \1 + through \9 = parenthetical subexpression from S. \ at end of + line appends next line of SCRIPT. The flags in F are: + [0-9] A number N, substitute only Nth match + g Global, substitute all matches i/I Ignore case when matching - p Print the line if match was found and replaced - w [file] Write (append) line to file if match replaced - - t [label] Test, jump to :label only if an "s" command found a match in - this line since last test (replacing with same text counts) - - T [label] Test false, jump only if "s" hasn't found a match. - - w [file] Write (append) line to file - + p Print resulting line when match found and replaced + w [file] Write (append) line to file when match replaced + t LABEL Test, jump if s/// command matched this line since last test + T LABEL Test false, jump to :LABEL only if no s/// found a match + w FILE Write (append) line to file y/old/new/ Change each character in 'old' to corresponding character in 'new' (with standard backslash escapes, delimiter can be any repeated character except \ or \n) - : [label] Labeled target for jump commands + The TEXT arguments (to a c i) may end with an unescaped "\" to append + the next line (leading whitespace is not skipped), and treat ";" as a + literal character (use "\;" instead). - # Comment, ignore rest of this line of SCRIPT - Deviations from POSIX: allow extended regular expressions with -r, - editing in place with -i, separate with -s, NUL-separated input with -z, - printf escapes in text, line continuations, semicolons after all commands, - 2-address anywhere an address is allowed, "T" command, multiline - continuations for [abc], \; to end [abc] argument before end of line. */ #define FOR_sed |