mirror of https://github.com/GnoConsortium/gno.git
137 lines
3.8 KiB
Groff
137 lines
3.8 KiB
Groff
.TH DSORT 1 "14 June 1994" GNO "Commands and Applications"
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.SH NAME
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dsort, msort \- sort text files lexicographically
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.SH SYNOPSIS
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.B msort
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[
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.I -hvV?
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] [
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.I "-o outfile"
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] [
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.I "-n lines"
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]
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.I file1
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[
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.I "file2 ..."
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]
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.LP
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.B dsort
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[
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.I -hvV?
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] [
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.I "-l length"
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] [
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.I "-n lines"
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] [
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.I "-o outfile"
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] [\fI-t path1\fR[,\fIpath2\fR[,\fIpath3\fR[,\fIpath4\fR]]]] \fIinfile\fR
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.SH DESCRIPTION
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This manual page documents
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.BR dsort
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and
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.BR msort
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version 1.0.
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.LP
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.BR dsort " and " msort
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are robust text file sorting utilities. While they do not support a lot
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of features, they are designed to sort large (and small) files very quickly.
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.LP
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.B msort
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is an in-place memory sort. Since it uses the heapsort algorithm, it is
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O[n lg n] both on average and for worst-case. Provided it has enough memory,
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.BR msort
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will sort files with lines of arbitrary length. Unless overridden by the
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.I -n
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flag,
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.BR msort
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will sort files of up to 1000 lines. Larger files can be sorted provided
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there is sufficient core memory. If multiple input files are given, the
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output is the concatenated result of sorting the input files separately.
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Thus, the following would be equivalent:
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.LP
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.nf
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% msort file1 file2 file3 >outfile
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and
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% msort file1 >file1out
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% msort file2 >file2out
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% cat file1out file2out >outfile
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.fi
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.LP
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.B dsort
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is a disk sort intended for files too large to be sorted in memory. It
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uses a four-file polyphase merge algorithm. Since it is an I/O-bound
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program,
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.BR dsort "'s
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speed is very dependant on the speed of the device used for temporary files.
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By default,
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.BR dsort
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will sort files with lines up to 512 characters long. Lines with more
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characters will be trucated unless the
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.I -l
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flag is used. Also by default, 1000 lines at a time will be sorted in
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memory during the collection (first) phase of the merge sort algorithm.
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This can be changed using the
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.I -n
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flag.
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.BR dsort
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will accept only one input file.
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.LP
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Both
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.BR dsort " and " msort
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leave the input file(s) intact.
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.SH OPTIONS
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.nf
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\fI-h\fR \fI-?\fR -- print version and usage info, then exit
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\fI-l\fR \fIlength\fR -- use a line length of \fIlength\fR
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\fI-n\fR \fIlines\fR -- sort \fIlines\fR lines in memory, (for \fBdsort\fR); don't
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try to sort files over \fIlines\fR long (for \fBmsort\fR).
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\fI-o\fR \fIoutfile\fR -- send sorted output to \fIoutfile\fR rather than to stdout
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\fI-t\fR \fIpathlist\fR -- use \fIpathlist\fR as the locations of temp files. If any
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of these are not specified, dsort will attempt to use
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the directory specified by the environment variable
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$(TMPDIR), then the system default temp path.
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\fI-v\fR -- verbose operation
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\fI-V\fR -- print version information
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.fi
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.SH HINTS
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If you have more than one fast drive, the speed of
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.B dsort
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can in general be improved by using four different drives for the
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path list when using
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.I -t .
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The best speed observed, however, has occurred when $(TMPDIR) or /tmp
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reside on a RAM disk or ROM disk.
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It is not suggested that floppies be used for temporary files.
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.SH RESOURCE USAGE
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Both
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.BR dsort " and " msort
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use 1k of stack space.
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.LP
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.BR msort
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is an in-place sort, so in general the amount of core memory used is
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the same as the size of the file to be sorted. When sorting multiple
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files,
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.BR msort "'s
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memory usage will match the size of the largest input file, not the
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total of all files. It will use a minimum of approximately 4k of core
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memory.
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.LP
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.BR dsort
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by default uses approximately 512k of core memory. This can be modified
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by changing the
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.I -l
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and
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.I -n
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parameters. Core memory usage is approximately the product of these two
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parameters.
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.LP
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When using
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.BR dsort ,
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the amount free space on the temporary path(s) must be at least twice
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the size of the file to be sorted.
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.SH AUTHOR
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Devin Reade \- glyn@cs.ualberta.ca
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.SH SEE ALSO
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.BR sort (1),
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.BR uniq (1).
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