Pick-From-a-List Toolsmy favorite heretical UNIX programs

I used Gary Bernhardt’s selecta script for a long time. I couldn’t summarize it better than the README:

• Pass it a list of choices on stdin.

• It will present a pretty standard fuzzy selection interface to the user (and block until they make a selection or kill it with ^C).

• It will print the user’s selection on stdout.

For example, you can say:

cat $(ls *.txt | selecta)

Putting a user-interface interaction in the middles of shell pipelines breaks some fundamental assumptions of the UNIX-y small-scripts-composition world, even with selecta opening /dev/tty directly, so the pipelines of standard streams aren’t broken. But that impurity has very often been worthwhile for interactive scripts I run many time a day. Turning a required argument into an optional argument that the computer can help me fill out correctly lightens the burden on me as I invoke scripts.

For example, I’ve used a script for years that basically boils down to:

1. Clone a Git repo with my to-do lists if it’s not cloned already.
2. Show the names of all its files and have me pick one.
3. Run $EDITOR on that file.
4. When $EDITOR quits, commit the changes and push them.

#!/bin/sh
set -e

# Clone the Git repo if it's not cloned already.
repo=~/todo
if ! test -d "$repo"; then
  git clone "you@git.host.com:todo" "$repo"
fi
cd "$repo"

# Pick a file and edit it.
file="$(git ls-files | fzf --no-multi --reverse --bind enter:accept-or-print-query)"
$EDITOR "$file"

# Commit and push.
git add "$file"
git commit --allow-empty-message -m ''
git push

Beyond to-do lists, I use pick-from-a-list in many other scripts. Just a few that come to mind:

• Scripts help me add or edit entries into various personal wikis.
• Scripts to update my list of postal shipments when tracking numbers come in, ETAs get updated, or packages arrive.
• Scripts to help me file “turns”, or revisions, of legal documents in my law practice.
• Scripts to help me upload files to cloud storage with rclone.
• Scripts to download and read PDFs from my personal library.
• Scripts to load and copy checklists for various tasks.
• Scripts to mark tasks off my to-do lists.

More recently, I’ve switched out selecta for gum and fzf, and even more recently just to fzf at the terminal, with either dmenu or rofi in dmenu-mode for scripts in a graphical environment.

The final move to fzf came from finding options that allow entering arbitrary input in addition to selecting an option from the list:

fzf \
  --no-multi \
  --reverse \
  --bind enter:accept-or-print-query

This basically means “pick a line from stdin or enter a new one”, rather than just “pick a line from stdin”.

I prefer fzf’s interface and the way it handles buffered input, so fzf with the --bind option beat out my last lingering use of gum filter:

gum filter \
  --no-strict \
  --width=0 # As wide as the terminal.

I still use gum for other kinds of interactive input taking:

gum input \
  --prompt="" \
  --placeholder="" \
  --value="" \
  --width=0 # As wide as the terminal.

Or to answer yes-or-no questions:

gum confirm "$question"

Good tool.

On the GUI side, I’ve long used the dwm tiling window manager with dmenu globally bound to Super+P as quick command runner. dmenu is, in essence, another pick-from-a-list tool, but one that displays lists graphically.

Sometimes it’s handy to run another script that uses a picker from dmenu, but there’s no displayed interactive terminal when doing so. So I’ve tweaked my scripts to check whether they’re hooked up to a terminal, then run fzf if they are or a graphical picker if they’re not:

have() {
  command -v "$1" >/dev/null
}

if [ -t 0 ]; then
  picker="fzf --no-multi --reverse"
else
  if have rofi; then
    picker="rofi -dmenu -theme arthur -dpi 1 -i"
  elif have dmenu; then
    picker="dmenu -i -l 10"
  else
    notify-send \
      -u critical \
      "Couldn't find rofi or demnu on PATH."
    exit 1
  fi
fi

rofi is a more broadly-scoped, richly configurable graphical pick-from-a-list tool that also offers a dmenu compatibility mode. I like to use it with a theme that makes it look different from my dmenu UI for running commands.

Notice also the use of notify-send, from libnotify Arch or libnotify-bin Debian, to give feedback. Again, when the script isn’t connected to a terminal, we need a way to present messages in the graphical environment instead.

rofi’s display also makes it more ideal for tasks like inserting emoji:

#!/bin/sh
set -e

emoji="$(rofi -show emoji -dpi 1)"
# Copy to primary selection / clipboard.
printf "%s" "$emoji" \
  | xclip -in -selection primary

# Paste from primary selection
# into the active user interface.
sleep 0.1
xdotool key shift+Insert

Your thoughts and feedback are always welcome by e-mail.

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