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.TH CAT 1
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.SH NAME
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cat, read \- catenate files
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.SH SYNOPSIS
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.B cat
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[
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.I file ...
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]
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.br
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.B read
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[
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.B -m
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] [
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.B -n
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.I nline
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] [
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.I file ...
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]
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.SH DESCRIPTION
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.I Cat
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reads each
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.I file
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in sequence and writes it on the standard output.
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Thus
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.IP
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.L
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cat file
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.LP
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prints a file and
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.IP
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.L
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cat file1 file2 >file3
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.LP
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concatenates the first two files and places the result
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on the third.
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.PP
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If no
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.I file
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is given,
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.I cat
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reads from the standard input.
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Output is buffered in blocks matching the input.
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.PP
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.I Read
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copies to standard output exactly one line from the named
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.IR file ,
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default standard input.
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It is useful in interactive
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.IR rc (1)
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scripts.
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.PP
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The
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.B -m
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flag causes it to continue reading and writing multiple lines until end of file;
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.B -n
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causes it to read no more than
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.I nline
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lines.
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.PP
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.I Read
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always executes a single
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.B write
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for each line of input, which can be helpful when
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preparing input to programs that expect line-at-a-time data.
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It never reads any more data from the input than it prints to the output.
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.SH SOURCE
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.B /sys/src/cmd/cat.c
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.br
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.B /sys/src/cmd/read.c
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.SH SEE ALSO
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.IR cp (1)
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.SH DIAGNOSTICS
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.I Read
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exits with status
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.B eof
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on end of file or, in the
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.B -n
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case, if it doesn't read
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.I nlines
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lines.
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.SH BUGS
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Beware of
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.L "cat a b >a"
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and
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.LR "cat a b >b" ,
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which
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destroy input files before reading them.