cut.1

<B>Digital的Unix操作系统VAX 4.2源码</B>

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.TH cut 1
.SH Name
cut \- cut out selected fields of each line of a file
.SH Syntax
\fBcut \-c\fR\fIlist\fR [\|\fIfile1 file2...\fR]
.br
\fBcut \-f\fR\fIlist\fR [\fB\-d\fIchar\fR\|] [\fB\-s\fR] [\|\fIfile1 file2...\fR]
.SH Description
.NXR "cut command"
.NXR "file" "cutting fields from"
.NXA "grep command" "cut command"
.NXA "cut command" "paste command"
Use the
.PN cut
command
to cut out columns from a table or 
fields from each line of a file.  
The fields as specified by
.I list\^
can be fixed length,
that is, character positions as on a punched card
(\fB\-c\fP option), or the length can vary from line to line
and be marked with a field delimiter character like
.I tab\^
(\fB\-f\fP option).
The
.PN cut
command can be used as a filter.
If no files are given, the standard input is used.
.PP
Use
.MS grep 1
to make horizontal ``cuts''
(by context) through a file, or
.MS paste 1
to put files together in columns.
To reorder columns in a table, use
.PN cut
and
.PN paste .
.SH Options
.NXR "cut command" "options"
.TP 12
.I list
Specifies ranges that must be a
comma-separated 
list of integer field numbers in increasing order.
With optional \fB\-\fP indicates ranges
as in the 
.B \-o
option of
nroff/troff
for page ranges;
for example,
.BR 1,4,7 ;
.BR 1\-3,8 ;
.B \-5,10
(short for \fB1\-5,10\fP); or
.B 3\-
(short for third through last field).
.TP
.BI \-c list
Specifies character
positions to be cut out. 
For example,
.B \-c1\-72
would pass the first 72 characters
of each line.
.TP
.BI \-f list
Specifies the fields to be cut out.
For example,
.B \-f1,7
copies the first and seventh field only.
Lines with no field delimiters are passed through intact (useful
for table subheadings), unless 
.B \-s
is specified.
.TP
.BI \-d char
Uses the specified character as the field delimiter.  
Default is
.IR tab .
Space or other characters with
special meaning to the shell must be quoted.
The \fB\-d\fP option is used only in combination with the 
\fB\-f\fP option, according to XPG3 and SVID2/SVID3.
.TP
.B \-s
Suppresses lines with no delimiter characters.   
Unless specified, lines with no delimiters 
are passed through untouched.  Either the
.B \-c
or 
.B \-f
option must be specified.
.SH Examples
Mapping of user \s-1ID\s0s to names:
.EX 5
cut \-d: \-f1,5 /etc/passwd
.EE
To set 
.B name
to the current login
name for the csh shell:
.EX 5
set name=`who am i | cut \-f1 \-d" "\*`
.EE
To set 
.B name
to the current login
name for the sh, sh5, and ksh shells:
.EX 5
name=`who am i | cut \-f1 \-d" "\*`
.EE
.SH Diagnostics
.TP 20
"line too long\^"
A line can have no more than 511 characters or fields.
.TP
"bad list for c\|/\|f option\^"
Missing 
.B \-c
or 
.B \-f
option or incorrectly specified
.IR list .
No error occurs if a line has fewer fields than the
.I list\^
calls for.
.TP
"no fields\^"
The
.I list\^
is empty.
.SH See Also
grep(1), paste(1)