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xpipe(1) General Commands Manual xpipe(1) NAME xpipe -- split input and feed it into the given utility SYNOPSIS xpipe [-Ic] [-J replstr] [-b bytes] [-n lines] [-p pattern] [utility [argument ...]] DESCRIPTION The xpipe command reads input from stdin and splits it by the given number of bytes, lines, or if matching the given pattern. It then in- vokes the given utility repeatedly, feeding it the generated data chunks as input. OPTIONS The following options are supported by xpipe: -I Do not write incomplete data. -J replstr When constructing the command to execute, replace the oc- currence of replstr with the integer representing the num- ber of invocation performed. -b num Split input every num bytes. -c Continue even if utility failed. -n num Split input every num lines. -p pattern Split input by the given pattern. See section PATTERNS for details. DETAILS xpipe conceptually combines some of the functionality of the split(1), tee(1), and xargs(1) utilities. That is, it allows for repeated execu- tion of the given utitity, but unlike xargs(1), xpipe allows you to split the input and pipe it into the utility rather than passing it as arguments. This allows you to process input either in byte-, line-, or pattern- separated chunks and pipe those chunks into the same tool without hav- ing to manually split the input or store data in temporary files. Input processing is done sequentially: data is read up until the end of the given pattern (or until the given number of bytes or lines has been encountered); when that condition is encountered, utility is invoked and the data chunk is written into a pipe to that process; xpipe then waits for the process to complete, upon which it continues to read in- put. If EOF is reached before the given condition is met, then xpipe will execute utility and pipe into it whatever data it encountered so far. This can be avoided by passing the -I flag, which leads to xpipe dis- carding any partial data without invoking utility (again or at all). PATTERNS When the -p flag is specified, xpipe will split input by the given pat- tern with each chunk including the pattern as the last bytes. A pattern is, by and large, a simple, fixed string. That is, you can- not specify regular expressions or shell globs; all characters or bytes are matched verbatim with the exception of the following: ^ If the '^' character is specified at the beginning of the pattern, then it will anchor the pattern at the beginning of the line. To match a literal '^' at the beginning of the line, escape the character using '^\^'. For example, to match a line beginning with the string '^foo', you'd use the pattern '^\^foo'. $ If the '$' character is specified at the end of the pattern (i.e., as the last character), then it will anchor the pattern at the end of the line. To match a literal '$' at the end of the line, escape the charac- ter using '\$$'. For example, to match a line ending with 'foo', you'd use the pattern 'foo$'; To match a line ending with 'foo$', you'd use 'foo\$$'. \n This will match a new line (ASCII 10). The difference to '$' is that you can match a \n anywhere in your pattern, while a '$' will only match at the end of he line. For example, to match a line ending in 'foo' followed by a line beginning with 'bar', you'd use the pattern 'foo\nbar'. \t This will match a tab character (ASCII 9). For example, to match a line beginning with two tabs followed by the string 'foo', you'd use the pattern '^\t\tfoo'. COMMAND INVOCATION xpipe will invoke the given utility with any subsequent arguments. If the -J flag is specified, then the given replstr in any of the argu- ments (including the utility itself) will be replaced with the number of the invocation. Since I/O redirection is processed by the invoking shell, you'd have to invoke a new shell to allow for redirection to e.g. a per-invocation output file. For example, to split the input into unique files ending in the given pattern: <input xpipe -J % -p pattern /bin/sh -c "cat >%.out" EXAMPLES The following examples illustrate common usage of this tool. To count the number of words in each paragraph of 'Don Quijote': curl -s https://www.gutenberg.org/cache/epub/2000/pg2000.txt | \ tr -d '^M' | \ xpipe -p '^$' wc -w To extract the subjects of all certificates in a standard PEM formatted x.509 trust bundle: <certs.pem xpipe -p '^-----END CERTIFICATE-----$' \ openssl x509 -noout -subject To split a large, uncompressed log file into multiple, compressed files, named 1.gz, 2.gz, ... n.gz: <logfile xpipe -n 1000 -J % /bin/sh -c "gzip >%.gz" EXIT STATUS The xpipe command exits with a value of 0 if no error occurs. If the -c flag is passed, xpipe will exit with an integer value repre- senting the total number of invocations of the utility that failed. If the -c was not passed, then any failure in the execution of the utility leads to the termination of xpipe. That is, if the utility cannot be found, xpipe exits with a value of 127; if utility cannot be executed, xpipe exits with a value of 126; if utility terminated be- cause of a signal, xpipe exits with a value of 125. If any other error occurs, xpipe exits with a value of 1. SEE ALSO split(1), tee(1), xargs(1) HISTORY xpipe was originally written by Jan Schaumann <jschauma@netmeister.org> in January 2020. BUGS Please file bugs and feature requests by emailing the author. FreeBSD ports 15.0 January 12, 2020 xpipe(1)
NAME | SYNOPSIS | DESCRIPTION | OPTIONS | DETAILS | PATTERNS | COMMAND INVOCATION | EXAMPLES | EXIT STATUS | SEE ALSO | HISTORY | BUGS
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