DBCOL(1)

💖 dbcol(1) — select columns from an Fsdb file 💖

okay so bestie, this is the manual page for dbcol, section 1, from the User Contributed Perl Documentation — and it’s literally all about selecting columns from an Fsdb file. no cap. 🦋

---

✨ NAME ✨

dbcol — select columns from an Fsdb file.

🌈 SYNOPSIS 🌈

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

🎀 DESCRIPTION 🎀

Okay so dbcol selects 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 — not a vibe. 😭

Note: a safer way to create columns is dbcolcreate. periodt.

💅 OPTIONS 💅

• -r, --relaxed-errors — Relaxed error checking: ignore columns that aren’t there. lowkey forgiving. 🫶
• -v, --invert-match — Output all columns except those listed (like grep -v). classic invert-match slay.
• -a, --all — Output all columns, in addition to those listed. (Thus "-a foo" will move column foo to the first column.) iconic rearrangement behavior.
• -e EmptyValue, --empty — Specify the value newly created columns get. this is the empty-value main character. ✨
• --saveoutput $OUT_REF — Save output writer (for integration with other fsdb filters). iykyk.

and the standard fsdb options:

• -d — Enable debugging output.
• -i InputSource, --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 OutputDestination, --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, --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. (yes, “then input” is what the page says, bestie — copy-paste energy preserved 💀)
• --help — Show help.
• --man — Show full manual.

🍓 SAMPLE USAGE 🍓

okay bestie, here’s the little demo. watch it glow. 🌟

🧚 Input:

#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

🧚 Command:

cat DATA/passwd.fsdb account | dbcol account

🧚 Output:

#fsdb      account
johnh
greg
root
# this is a simple database
#  | dbcol account

🔥 SEE ALSO 🔥

dbcolcreate(1), Fsdb(3)

👑 AUTHOR and COPYRIGHT 👑

Copyright (C) 1991-2022 by John Heidemann <johnh@isi.edu>

This program is distributed under terms of the GNU general public license, version 2. See the file COPYING with the distribution for details.

🫶 okay that’s the whole page, bestie. this one came from perl v5.32.1, dated 2024-08-02, and the manual name is DBCOL(1) — slay and goodbye. 💜