1DBCOL(1) User Contributed Perl Documentation DBCOL(1)
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6 dbcol - select columns from an Fsdb file
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9 dbcol [-v] [-e -] [column...]
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12 Select one or more columns from the input database. If a value is
13 given for empty columns with the -e option, then any named columns
14 which don't exist will be created. Otherwise, non-existent columns are
15 an error.
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17 Note: a safer way to create columns is dbcolcreate.
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20 -r or --relaxed-errors
21 Relaxed error checking: ignore columns that aren't there.
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23 -v or --invert-match
24 Output all columns except those listed (like grep -v).
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26 -e EmptyValue or --empty
27 Specify the value newly created columns get.
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29 and the standard fsdb options:
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31 -d Enable debugging output.
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33 -i or --input InputSource
34 Read from InputSource, typically a file, or - for standard input,
35 or (if in Perl) a IO::Handle, Fsdb::IO or Fsdb::BoundedQueue
36 objects.
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38 -o or --output OutputDestination
39 Write to OutputDestination, typically a file, or - for standard
40 output, or (if in Perl) a IO::Handle, Fsdb::IO or
41 Fsdb::BoundedQueue objects.
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43 --autorun or --noautorun
44 By default, programs process automatically, but Fsdb::Filter
45 objects in Perl do not run until you invoke the run() method. The
46 "--(no)autorun" option controls that behavior within Perl.
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48 --header H
49 Use H as the full Fsdb header, rather than reading a header from
50 then input.
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52 --help
53 Show help.
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55 --man
56 Show full manual.
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59 Input:
60 #fsdb account passwd uid gid fullname homedir shell
61 johnh * 2274 134 John_Heidemann /home/johnh /bin/bash
62 greg * 2275 134 Greg_Johnson /home/greg /bin/bash
63 root * 0 0 Root /root /bin/bash
64 # this is a simple database
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66 Command:
67 cat DATA/passwd.fsdb account | dbcol account
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69 Output:
70 #fsdb account
71 johnh
72 greg
73 root
74 # this is a simple database
75 # | dbcol account
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78 dbcolcreate(1), Fsdb(3)
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81 Copyright (C) 1991-2018 by John Heidemann <johnh@isi.edu>
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83 This program is distributed under terms of the GNU general public
84 license, version 2. See the file COPYING with the distribution for
85 details.
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89perl v5.28.1 2019-02-02 DBCOL(1)