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dbcol - Man Page

select columns from an Fsdb file


dbcol [-v] [-e -] [column...]


Select one or more columns from the input database. If a value is given for empty columns with the -e option, then any named columns which don't exist will be created. Otherwise, non-existent columns are an error.

Note:  a safer way to create columns is dbcolcreate.


-r or --relaxed-errors

Relaxed error checking: ignore columns that aren't there.

-v or --invert-match

Output all columns except those listed (like grep -v).

-a or --all

Output all columns, in addition to those listed. (Thus -a foo will move column foo to the first column.)

-e EmptyValue or --empty

Specify the value newly created columns get.

--saveoutput $OUT_REF

Save output writer (for integration with other fsdb filters).

and the standard fsdb options:


Enable debugging output.

-i or --input InputSource

Read from InputSource, typically a file, or - for standard input, or (if in Perl) a IO::Handle, Fsdb::IO or Fsdb::BoundedQueue objects.

-o or --output OutputDestination

Write to OutputDestination, typically a file, or - for standard output, or (if in Perl) a IO::Handle, Fsdb::IO or Fsdb::BoundedQueue objects.

--autorun or --noautorun

By default, programs process automatically, but Fsdb::Filter objects in Perl do not run until you invoke the run() method. The --(no)autorun option controls that behavior within Perl.

--header H

Use H as the full Fsdb header, rather than reading a header from then input.


Show help.


Show full manual.

Sample Usage


    #fsdb account passwd uid gid fullname homedir shell
    johnh * 2274 134 John_Heidemann /home/johnh /bin/bash
    greg * 2275 134 Greg_Johnson /home/greg /bin/bash
    root * 0 0 Root /root /bin/bash
    # this is a simple database


    cat DATA/passwd.fsdb account | dbcol account


    #fsdb      account
    # this is a simple database
    #  | dbcol account

See Also

dbcolcreate(1), Fsdb(3)


2024-07-01 perl v5.40.0 User Contributed Perl Documentation