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Pipeline Patterns and Script Design

The Two Patterns of fzf Scripting​

Pattern 1: Inline Pipe​

# Source → fzf → Consumer in one line
docker ps --format "{{.Names}}" | fzf | xargs docker exec -it -e TERM=xterm bash

Simple, readable. Ideal for one-off commands and aliases.

Pattern 2: Capture + Branch​

# Capture selection, check exit code, branch
selected=$(ls | fzf)
case $? in
  0)   nvim "$selected" ;;      # success
  1)   echo "No match" ;;       # no results
  130) echo "Cancelled" ;;      # Esc / CTRL-C
esac

More control. Ideal for shell functions.

Chaining Multiple fzf Pickers​

Two-step selector: namespace → pod
# Pick Kubernetes namespace, then pick pod in that namespace
k8s_exec() {
  local ns pod
  ns=$(kubectl get namespaces -o jsonpath='{.items[*].metadata.name}' \
    | tr ' ' '\n' | fzf --prompt 'Namespace> ' --height=40%)
  [[ -z "$ns" ]] && return

  pod=$(kubectl get pods -n "$ns" --no-headers \
    | awk '{print $1, $3}' \
    | fzf --prompt "Pod ($ns)> " --height=40% \
    | awk '{print $1}')
  [[ -z "$pod" ]] && return

  kubectl exec -it -n "$ns" "$pod" -- bash
}

Non-interactive Batch Mode (--filter)​

Use --filter to run fzf as a fuzzy grep without opening the TUI:

# Find all files matching "config" fuzzily (no TUI)
ls | fzf --filter="config"

# Use in scripts where there's no TTY
find . -type f | fzf --filter="test" | head -5

# Pipe into further processing
ls /etc | fzf --filter="nginx" | xargs cat

Handling No Selection Gracefully​

pick_file() {
  local file
  file=$(find . -type f | fzf) || {
    # fzf exits non-zero on cancel or no-match
    echo "No file selected." >&2
    return 1
  }
  echo "$file"
}

# Usage
if file=$(pick_file); then
  nvim "$file"
fi

fzf Without a TTY (Script Context)​

fzf requires a TTY for the interactive TUI. In non-interactive environments, handle gracefully:

pick_or_default() {
  local default="$1"
  shift
  if [ -t 1 ]; then
    # TTY available: use interactive fzf
    printf '%s\n' "$@" | fzf --prompt 'Select> '
  else
    # No TTY: return default
    echo "$default"
  fi
}

Building a CLI Tool with fzf​

fman-all: a complete man page browser
#!/usr/bin/env bash
# fman-all: fuzzy man page browser with sections
set -euo pipefail

PROMPT="📖 Man Pages> "
PREVIEW='man $(echo {} | awk "{print \$1}") 2>/dev/null | head -60 || echo "No preview"'

main() {
  local selection key
  local out
  out=$(man -k . 2>/dev/null | sort -u | fzf \
    --ansi \
    --expect=ctrl-c \
    --preview "$PREVIEW" \
    --preview-window 'right:60%:wrap' \
    --prompt "$PROMPT" \
    --header $'Enter: open  Ctrl+C: quit\nSearch: name or description' \
    --bind 'ctrl-/:toggle-preview')

  key=$(head -1 <<< "$out")
  selection=$(tail -1 <<< "$out")

  [[ "$key" == "ctrl-c" || -z "$selection" ]] && exit 0

  local page section
  page=$(echo "$selection" | awk '{print $1}')
  section=$(echo "$selection" | grep -oP '\(\K[^\)]+')

  man "${section:+-s $section}" "$page"
}

main "$@"

Environment Variable Pattern​

Override fzf options per function
# Each function can override defaults cleanly
fzf_with_opts() {
  FZF_DEFAULT_OPTS="$FZF_DEFAULT_OPTS $1" fzf "${@:2}"
}

# Usage
ls | fzf_with_opts "--height=20 --prompt='File> '"

What's Next​