How to get the number of files in a folder as a variable?

Question

Using bash, how can one get the number of files in a folder, excluding directories from a shell script without the interpreter complaining?

With the help of a friend, I've tried

$files=$(find ../ -maxdepth 1 -type f | sort -n)
$num=$("ls -l" | "grep ^-" | "wc -l")

which returns from the command line:

../1-prefix_blended_fused.jpg: No such file or directory
ls -l :  command not found
grep ^-: command not found
wc -l:   command not found

respectively. These commands work on the command line, but NOT with a bash script.

Given a file filled with image files formatted like 1-pano.jpg, I want to grab all the images in the directory to get the largest numbered file to tack onto the next image being processed.

Why the discrepancy?

Answer 1

The quotes are causing the error messages.

To get a count of files in the directory:

shopt -s nullglob
numfiles=(*)
numfiles=${#numfiles[@]}

which creates an array and then replaces it with the count of its elements. This will include files and directories, but not dotfiles or . or .. or other dotted directories.

Use nullglob so an empty directory gives a count of 0 instead of 1.

You can instead use find -type f or you can count the directories and subtract:

# continuing from above
numdirs=(*/)
numdirs=${#numdirs[@]}
(( numfiles -= numdirs ))

Also see "How can I find the latest (newest, earliest, oldest) file in a directory?"

You can have as many spaces as you want inside an execution block. They often aid in readability. The only downside is that they make the file a little larger and may slow initial parsing (only) slightly. There are a few places that must have spaces (e.g. around [, [[, ], ]] and = in comparisons) and a few that must not (e.g. around = in an assignment.

Answer 2

ls -l | grep -v ^d | wc -l

One line.

Answer 3

How about:

count=$(find .. -maxdepth 1 -type f|wc -l)
echo $count
let count=count+1 # Increase by one, for the next file number
echo $count

Note that this solution is not efficient: it spawns sub shells for the find and wc commands, but it should work.

Answer 4

The most straightforward, reliable way I can think of is using the find command to create a reliably countable output.

Counting characters output of find with wc:

find . -maxdepth 1 -type f -printf '.' | wc --char

or string length of the find output:

a=$(find . -maxdepth 1 -type f -printf '.')
echo ${#a}

or using find output to populate an arithmetic expression:

echo $(($(find . -maxdepth 1 -type f -printf '+1')))

Answer 5

file_num=$(ls -1 --file-type | grep -v '/$' | wc -l)

this is a bit lightweight than a find command, and count all files of the current directory.

Answer 6

Simple efficient method:

#!/bin/bash
RES=$(find ${SOURCE} -type f | wc -l)

Answer 7

Get rid of the quotes. The shell is treating them like one file, so it's looking for "ls -l".

Answer 8

Short and sweet method which also ignores symlinked directories.

count=$(ls -l | grep ^- | wc -l)

or if you have a target:

count=$(ls -l /path/to/target | grep ^- | wc -l)

Answer 9

REmove the qoutes and you will be fine

Answer 10

Expanding on the accepted answer (by Dennis W): when I tried this approach I got incorrect counts for dirs without subdirs in Bash 4.4.5.

The issue is that by default nullglob is not set in Bash and numdirs=(*/) sets an 1 element array with the glob pattern */. Likewise I suspect numfiles=(*) would have 1 element for an empty folder.

Setting shopt -s nullglob to disable nullglobbing resolves the issue for me. For an excellent discussion on why nullglob is not set by default on Bash see the answer here: Why is nullglob not default?

Note: I would have commented on the answer directly but lack the reputation points.

Answer 11

Here's one way you could do it as a function. Note: you can pass this example, dirs for (directory count), files for files count or "all" for count of everything in a directory. Does not traverse tree as we aren't looking to do that.

function get_counts_dir() {

    # -- handle inputs (e.g. get_counts_dir "files" /path/to/folder)
    [[ -z "${1,,}" ]] && type="files" || type="${1,,}"
    [[ -z "${2,,}" ]] && dir="$(pwd)" || dir="${2,,}"

    shopt -s nullglob
    PWD=$(pwd)
    cd ${dir}

    numfiles=(*)
    numfiles=${#numfiles[@]}
    numdirs=(*/)
    numdirs=${#numdirs[@]}

    # -- handle input types files/dirs/or both
    result=0
    case "${type,,}" in
        "files")
            result=$((( numfiles -= numdirs )))
        ;;
        "dirs")
            result=${numdirs}
        ;;
        *)  # -- returns all files/dirs
            result=${numfiles}
        ;;

    esac

    cd ${PWD}
    shopt -u nullglob

    # -- return result --
    [[ -z ${result} ]] && echo 0 || echo ${result}
}

Examples of using the function :

folder="/home"
get_counts_dir "files" "${folder}"
get_counts_dir "dirs" "${folder}"
get_counts_dir "both" "${folder}"

Will print something like :

2
4
6