List number of lines in a file or in all files in a directory (non-recursive). Data is outputted in neat columns.

count_lines.sh

# author: Alex Stout 

# check if the provided argument is a directory
if [[ -d $1 ]]; then
  : # nop -- do nothing
elif [[ -f $1 ]]; then # or is it a file
  : # nop -- do nothing
else
  echo "argument is invalid"
  exit 1
fi

# function will count the number of lines in a file
__file_count=0
count_lines_in_file() {
  local __file=$1
  # echo "counting lines in file $__file"
  __file_count=$(grep -c ^ < "$__file")
}

# function will count the number of lines of every file in the given directory
__dir_count=0
count_lines_in_dir() {
  local __result=$1
  num_files=$(find $1 -type f -maxdepth 1 | wc -l)
  # echo "number of files: $num_files"
  i=0
  find $1 -type f -maxdepth 1 | while read FILE; do
    count_lines_in_file $FILE
    printf '%-15s%-25s%-5s\n' $1 $(basename $FILE) $__file_count
    ((__dir_count = __dir_count + __file_count))
    ((i = i + 1))
    if [[ $num_files -eq $i ]]; then
      printf '\nTOTAL LINES COUNTED:  %s\n' $__dir_count
    fi
  done
  # NOTE: you'd think you could add the total lines to __dir_count and print after the loop or even use the value outside the function,
  # but it doesn't work!
  # apparently using the pipe starts a new subprocess so the updates to the variable in that loop do not get applied to the parent process
  # there's probably some way around it, but I didn't care enough for the immediate use of this script
}

# Print a header for the data
printf '\n%-15s%-25s%-5s\n' 'Directory' 'File' 'Lines'

if [[ -d $1 ]]; then
  count_lines_in_dir $1
elif [[ -f $1 ]]; then
  count_lines_in_file $1
  printf '\nTOTAL LINES COUNTED:  %s\n' $__file_count
else
  echo "an error occurred"
  exit 1
fi

echo ""