スクリプトから呼ぶ fzf が返す値と終了コード

EXIT STATUS
     0      Normal exit
     1      No match
     2      Error
     126    Permission denied error from become action
     127    Invalid shell command for become action
     130    Interrupted with CTRL-C or ESC

-1, --select-1
       If there is only one match for the initial query (--query), do not start interactive finder and automatically select the only match
-0, --exit-0
       If there is no match for the initial query (--query), do not start interactive finder and exit immediately

$ printf 'deploy-prod\n' | fzf --select-1; echo "exit=$?"
deploy-prod
exit=0
$ printf 'deploy-prod\ndeploy-stg\n' | fzf --query prod --select-1; echo "exit=$?"
deploy-prod
exit=0
$ printf 'deploy-prod\ndeploy-stg\n' | fzf --query zzz --exit-0; echo "exit=$?"
exit=1

$ printf 'deploy-prod\ndeploy-stg\n' | fzf --query deploy --select-1; echo "exit=$?"
exit=130    # 一覧が出て、ESC を押した

$ names=$'apps-migration\nfeature-auth\nfix-login'
$ fzf --query api --select-1 <<<"$names"; echo "exit=$?"
apps-migration
exit=0
$ fzf --filter api --exact <<<"$names"; echo "exit=$?"    # --exact は部分文字列一致
exit=1

$ names2=$'domain-model\nfeature-auth'
$ fzf --query main --select-1 --exact <<<"$names2"; echo "exit=$?"
domain-model
exit=0
$ fzf --filter "'main" <<<"$names2"; echo "exit=$?"
domain-model
exit=0
$ fzf --filter '^main$' <<<"$names2"; echo "exit=$?"
exit=1
$ fzf --filter '^main$' <<<$'domain-model\nmain'; echo "exit=$?"
main
exit=0

$ rows=$'[merged] feature-auth\n[open] apps-migration'
$ fzf --query merged --select-1 --exact <<<"$rows"; echo "exit=$?"
[merged] feature-auth
exit=0
$ fzf --filter merged --exact --nth=-1 <<<"$rows"; echo "exit=$?"
exit=1

$ fzf --filter '!open' <<<"$rows"; echo "exit=$?"     # !open は「open を含まない行」
[merged] feature-auth
exit=0
$ fzf --filter '!open' --exact --no-extended <<<"$rows"; echo "exit=$?"
exit=1

args=(--prompt 'select> ')
if [[ -n $query ]]; then
  args+=(--query "$query" --select-1 --exact --no-extended --nth=-1)
fi
fzf "${args[@]}"

$ setsid -w bash -c 'printf "a\n" | fzf --select-1; echo "exit=$?"'
failed to open /dev/tty
exit=2
$ setsid -w bash -c 'printf "a\nb\n" | fzf --query a --select-1 --exact; echo "exit=$?"'
failed to open /dev/tty
exit=2
$ setsid -w bash -c 'printf "a\nb\n" | fzf --query zzz --exit-0; echo "exit=$?"'
failed to open /dev/tty
exit=2
$ setsid -w bash -c 'printf "a\nb\n" | fzf --filter a --exact; echo "exit=$?"'
a
exit=0

$ printf 'a\n' | fzf --expect= --select-1; echo "exit=$?"
key names required
exit=2
$ printf 'a\n' | fzf --expect=ctrl-v --select-1; echo "exit=$?"

a
exit=0

$ vim -Nu NONE -es ... -c 'unlet! g:fzf_action' -c 'let o = fzf#wrap({})' -c 'put =string(o.options)' ...
'  --expect=ctrl-v,ctrl-x,ctrl-t'
$ vim -Nu NONE -es ... -c 'let g:fzf_action = {}' -c 'let o = fzf#wrap({})' -c 'put =string(o.options)' ...
'  --expect='

let s:had_action = exists('g:fzf_action')
let s:saved_action = get(g:, 'fzf_action', {})
let g:fzf_action = {'ctrl-o': 'edit'}
put ='during: ' . fzf#wrap({}).options
if s:had_action
  let g:fzf_action = s:saved_action
else
  unlet! g:fzf_action
endif
put ='after: exists=' . exists('g:fzf_action') . fzf#wrap({}).options

during:   --expect=ctrl-o
after: exists=0  --expect=ctrl-v,ctrl-x,ctrl-t

set -o pipefail
produce() { echo first; sleep 2; seq 100000; }
sel=$(produce | fzf) || echo "fallback: status=$?"
echo "sel=$sel"
produce | fzf > /dev/null; echo "PIPESTATUS=${PIPESTATUS[*]}"

fallback: status=141
sel=first
PIPESTATUS=141 0

rows=$(produce)               # 先に出力を確定させる
sel=$(fzf <<<"$rows") || :    # パイプにしない

rows: 100001 lines
sel=first

Each expression expands to a quoted string, so that it's safe to pass it as an argument to an external command. So you should not manually add quotes around the curly braces.

$ line="it's a file.txt"
$ fzf --with-shell 'printf cmd=%s\n' --bind 'enter:become(printf "[%s]\n" {})' <<<"$line"
cmd=printf "[%s]\n" 'it'\''s a file.txt'
$ fzf --bind 'enter:become(printf "[%s]\n" {})' <<<"$line"
[it's a file.txt]

$ fzf --with-shell 'printf cmd=%s\n' --bind 'enter:become(printf "[%s]\n" "{}")' <<<"$line"
cmd=printf "[%s]\n" "'it'\''s a file.txt'"
$ fzf --bind 'enter:become(printf "[%s]\n" "{}")' <<<"$line"
['it'\''s a file.txt']

$ fzf --bind 'enter:become(printf "[%s]\n" {r})' <<<"a file.txt"
[a]
[file.txt]

$ printf '%s\t%s\n' "/srv/data/it's a file.txt" "it's a file" |
    fzf --delimiter '\t' --with-nth 2 --bind 'enter:become(printf "[%s]\n" {1})'
[/srv/data/it's a file.txt]

show() { echo "show: $1"; }
VAR=local-only
export EXPORTED=exported
fzf --preview 'echo "pid=$$ line={}" >> preview.out; show {} >> preview.out 2>&1; echo "VAR=$VAR EXPORTED=$EXPORTED" >> preview.out' \
  <<<$'a.txt\nb.txt'

pid=495 line='a.txt'
/bin/bash: line 1: show: command not found
VAR= EXPORTED=exported
pid=498 line='b.txt'
/bin/bash: line 1: show: command not found
VAR= EXPORTED=exported

#!/bin/bash
show() { echo "show: $1"; }
if [[ $1 == --preview-line ]]; then
  show "$2"
  exit
fi
self=$(readlink -f "$0")
cd /tmp || exit 1 # 一覧を作る前に別の場所へ移るスクリプトを想定する
fzf --preview "$self --preview-line {}" <<<$'a.txt\nb.txt'

show: a.txt

$ printf 'a\nb\nc\n' | fzf --multi
c
a

$ printf 'a\nb\nc\n' | nl -ba | fzf --multi --with-nth=2.. | sort -k1,1n | cut -f2-
a
c

list=$'my file.txt\nb.txt'
files=$(fzf --multi --bind 'load:select-all+accept' <<<"$list" | tr '\n' ' ')
printf '[%s]\n' $files

[my]
[file.txt]
[b.txt]

files=()
while IFS= read -r f; do
  [[ -n $f ]] && files+=("$f")
done < <(fzf --multi --bind 'load:select-all+accept' <<<"$list")
printf '[%s]\n' "${files[@]}"

[my file.txt]
[b.txt]

$ printf '1\n2\n3\n' | fzf                  # => 1
$ printf '1\n2\n3\n' | fzf --tac            # => 3
$ printf '1\n2\n3\n' | fzf --reverse        # => 1
$ printf '1\n2\n3\n' | fzf --tac --reverse  # => 3

fzf                   fzf --tac
  3                     1
  2                     2
> 1                   > 3
  3/3 ──────            3/3 ──────
>                     >

fzf --reverse         fzf --tac --reverse
>                     >
  3/3 ──────            3/3 ──────
> 1                   > 3
  2                     2
  3                     1