Bash – Getting the first file in a directory in bash

bashshell-script

How do you get the first file in a directory in bash? First being the what the shell glob finds first.

My search for getting the first file in a directory in bash brought me to an old post with a very specific request. I'd like to document my solution to the general question for posterity and make a place for people to put alternative solutions they'd like to share.

Best Answer

To get the first file in the current dir you can put the expansion in an array and grab the first element:

files=(*)
echo "${files[0]}"
# OR
echo "$files" # since we are only concerned with the first element

Assuming your current dir contains multiple dirs you can loop through and grab the first file like so:

for dir in *; do
    files=($dir/*)    
    echo "${files[0]}"
done

Related Solutions

Bash – Directory Shortcuts

The way I used to do this is to create a directory that contains symlinks to the directories you want shortcuts do, and add that directory to your CDPATH. CDPATH controls where cd will search when you switch directories, so if that directory of symlinks is in your CDPATH you can cd to any of the symlinked directories instantly:

mkdir ~/symlinks
ln -s /usr/bin ~/symlinks/b
export CDPATH=~/symlinks
cd b   # Switches to /usr/bin

The downside of course is it won't work if there's a directory in your current directory named "b" -- that takes precedence over the CDPATH

I normally dislike answers that say "first you need to switch shells", but this exact feature exists in ZSH, if you're willing to use that instead; it's called named directories. You export a variable foo, and when you refer to ~foo it resolves to the value of $foo. This is especially convenient because it works in commands besides cd:

echo hi > /tmp/test
export t=/tmp
cat ~t/test   # Outputs "hi"

Alternative Methods to Ctrl-R Reverse Search in Bash

I'm using the fuzzy finder program FZF. I've written my own key bindings and shell scripts to utilize FZF as my tool of choice to reverse-search an interactive Bash shell's history. Feel free to copy and paste the code from my Config GitHub repository.

~/.bashrc configuration file

# Test if fuzzy finder program _Fzf_ is installed.
#
if type -p fzf &> /dev/null; then

  # Test if _Fzf_ specific _Readline_ file is readable.
  #
  if [[ -f ~/.inputrc.fzf && -r ~/.inputrc.fzf ]]; then

    # Make _Fzf_ available through _Readline_ key bindings.
    #
    bind -f ~/.inputrc.fzf
  fi
fi

~/.inputrc.fzf configuration file ##

$if mode=vi

  # Key bindings for _Vi_ _Insert_ mode
  # ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  set keymap vi-insert

  "\C-x\C-a": vi-movement-mode
  "\C-x\C-e": shell-expand-line
  "\C-x\C-r": redraw-current-line
  "\C-x^": history-expand-line
  "\C-r": "\C-x\C-addi$(HISTTIMEFORMAT= history | fzf-history)\C-x\C-e\C-x\C-r\C-x^\C-x\C-a$a"

  # Key bindings for _Vi_ _Command_ mode
  # ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  set keymap vi-command

  "\C-r": "i\C-r"
  "\ec": "i\ec"

$endif

fzf-history executable Bash script

#!/usr/bin/env bash
#
# Retrieve command from history with fuzzy finder
# ===============================================
# Tim Friske <me@tifr.de>
#
# See also:
#   * man:bash[1]
#   * man:fzf[1]
#   * man:cat[1]

shopt -os nounset pipefail errexit errtrace
shopt -s extglob globstar

function print_help {
  1>&2 cat \
<<'HELP'
usage:
  HISTTIMEFORMAT= history | fzf-history
HELP
}

function fzf_history {
  if [[ -t 0 ]]; then
    print_help
    exit
  fi

  local fzf_options=()
  fzf_options+=(${FZF_DEFAULT_OPTS:-})
  fzf_options+=('--tac' '-n2..,..' '--tiebreak=index')
  fzf_options+=(${FZF_HISTORY_FZF_OPTS:-})
  fzf_options+=('--print0')

  local cmd='' cmds=()
  while read -r -d '' cmd; do
    cmds+=("${cmd/#+([[:digit:]])+([[:space:]])/}")
  done < <(fzf "${fzf_options[@]}")
  if [[ "${#cmds[*]}" -gt 0 ]]; then
    (IFS=';'; printf '%s\n' "${cmds[*]}")
  fi
}

fzf_history "$@"

key-bindings.bash sourceable Bash script

Taken and slightly adapted from FZF's Bash key bindings file here are the Emacs mode compatible key bindings for Bash's history reverse-search with Ctrl-R (untested):

if [[ ! -o vi ]]; then
  # Required to refresh the prompt after fzf
  bind '"\er": redraw-current-line'
  bind '"\e^": history-expand-line'

  # CTRL-R - Paste the selected command from history into the command line
  bind '"\C-r": " \C-e\C-u\C-y\ey\C-u$(HISTTIMEFORMAT= history | fzf-history)\e\C-e\er\e^"'
fi