awk/-F

• awk -F — field separator flag

  • -F sets the field separator (FS) used to split each input line into fields.
  • My Note by default the field separator is any whitespace (space or tab chars). awk -F is useful if you need to customize that some more.

  • Syntax

    • bash

      awk -F'<sep>' '{ ... }' file

    • <sep> can be a literal character or an ERE (extended regular expression).

  • How it works

    • Without -F, awk splits on runs of whitespace (spaces and tabs, collapsing consecutive ones).
    • With -F, each line is split on the given separator; fields are referenced as $1, $2, ... $NF.
    • The field separator is also available as the built-in variable FS; -F'\t' is equivalent to BEGIN { FS = "\t" }.

  • Common examples

    • Tab-separated input:
      • bash

        awk -F'\t' '{ print $1 }' file.tsv

    • Colon-separated (/etc/passwd):
      • bash

        awk -F':' '{ print $1 }' /etc/passwd

    • Comma-separated:
      • bash

        awk -F',' '{ print $2 }' file.csv

  • Example: filter only mapped Obsidian hotkeys

    • Obsidian/Q/Using the Obsidian CLI, what one-liner filters obsidian hotkeys to show only actually-mapped commands?
    • obsidian hotkeys outputs tab-separated lines — command ID in $1, key binding in $2 (empty if unmapped). -F'\t' splits on tab; $2 as a condition passes only lines where the second field is non-empty:
      • bash

        obsidian hotkeys | awk -F'\t' '$2'