Recursively counting files in a Linux directory

Question

How can I recursively count files in a Linux directory?

I found this:

find DIR_NAME -type f ¦ wc -l

But when I run this it returns

Answer 1

For directories with spaces in the name ... (based on various answers above) -- recursively print directory name with number of files within:

find . -mindepth 1 -type d -print0 | while IFS= read -r -d '' i ; do echo -n $i": " ; ls -p "$i" | grep -v / | wc -l ; done

---

Example (formatted for readability):

pwd
  /mnt/Vancouver/Programming/scripts/claws/corpus

ls -l
  total 8
  drwxr-xr-x 2 victoria victoria 4096 Mar 28 15:02 'Catabolism - Autophagy; Phagosomes; Mitophagy'
  drwxr-xr-x 3 victoria victoria 4096 Mar 29 16:04 'Catabolism - Lysosomes'

ls 'Catabolism - Autophagy; Phagosomes; Mitophagy'/ | wc -l
  138

## 2 dir (one with 28 files; other with 1 file):
ls 'Catabolism - Lysosomes'/ | wc -l
  29

The directory structure is better visualized using tree:

tree -L 3 -F .
  .
  ├── Catabolism - Autophagy; Phagosomes; Mitophagy/
  │   ├── 1
  │   ├── 10
  │   ├── [ ... SNIP! (138 files, total) ... ]
  │   ├── 98
  │   └── 99
  └── Catabolism - Lysosomes/
      ├── 1
      ├── 10
      ├── [ ... SNIP! (28 files, total) ... ]
      ├── 8
      ├── 9
      └── aaa/
          └── bbb

  3 directories, 167 files

man find | grep mindep
  -mindepth levels
    Do not apply any tests or actions at levels less than levels
    (a non-negative integer).  -mindepth 1 means process all files
    except the starting-points.

ls -p | grep -v / (used below) is from answer 2 at https://unix.stackexchange.com/questions/48492/list-only-regular-files-but-not-directories-in-current-directory

find . -mindepth 1 -type d -print0 | while IFS= read -r -d '' i ; do echo -n $i": " ; ls -p "$i" | grep -v / | wc -l ; done
./Catabolism - Autophagy; Phagosomes; Mitophagy: 138
./Catabolism - Lysosomes: 28
./Catabolism - Lysosomes/aaa: 1

---

Applcation: I want to find the max number of files among several hundred directories (all depth = 1) [output below again formatted for readability]:

date; pwd
    Fri Mar 29 20:08:08 PDT 2019
    /home/victoria/Mail/2_RESEARCH - NEWS

time find . -mindepth 1 -type d -print0 | while IFS= read -r -d '' i ; do echo -n $i": " ; ls -p "$i" | grep -v / | wc -l ; done > ../../aaa
    0:00.03

[victoria@victoria 2_RESEARCH - NEWS]$ head -n5 ../../aaa
    ./RNA - Exosomes: 26
    ./Cellular Signaling - Receptors: 213
    ./Catabolism - Autophagy; Phagosomes; Mitophagy: 138
    ./Stress - Physiological, Cellular - General: 261
    ./Ancient DNA; Ancient Protein: 34

[victoria@victoria 2_RESEARCH - NEWS]$ sed -r 's/(^.*): ([0-9]{1,8}$)/\2: \1/g' ../../aaa | sort -V | (head; echo ''; tail)

    0: ./Genomics - Gene Drive
    1: ./Causality; Causal Relationships
    1: ./Cloning
    1: ./GenMAPP 2
    1: ./Pathway Interaction Database
    1: ./Wasps
    2: ./Cellular Signaling - Ras-MAPK Pathway
    2: ./Cell Death - Ferroptosis
    2: ./Diet - Apples
    2: ./Environment - Waste Management

    988: ./Genomics - PPM (Personalized & Precision Medicine)
    1113: ./Microbes - Pathogens, Parasites
    1418: ./Health - Female
    1420: ./Immunity, Inflammation - General
    1522: ./Science, Research - Miscellaneous
    1797: ./Genomics
    1910: ./Neuroscience, Neurobiology
    2740: ./Genomics - Functional
    3943: ./Cancer
    4375: ./Health - Disease 

sort -V is a natural sort. ... So, my max number of files in any of those (Claws Mail) directories is 4375 files. If I left-pad (https://stackoverflow.com/a/55409116/1904943) those filenames -- they are all named numerically, starting with 1, in each directory -- and pad to 5 total digits, I should be ok.

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Addendum

Find the total number of files, subdirectories in a directory.

$ date; pwd
Tue 14 May 2019 04:08:31 PM PDT
/home/victoria/Mail/2_RESEARCH - NEWS

$ ls | head; echo; ls | tail
Acoustics
Ageing
Ageing - Calorie (Dietary) Restriction
Ageing - Senescence
Agriculture, Aquaculture, Fisheries
Ancient DNA; Ancient Protein
Anthropology, Archaeology
Ants
Archaeology
ARO-Relevant Literature, News

Transcriptome - CAGE
Transcriptome - FISSEQ
Transcriptome - RNA-seq
Translational Science, Medicine
Transposons
USACEHR-Relevant Literature
Vaccines
Vision, Eyes, Sight
Wasps
Women in Science, Medicine

$ find . -type f | wc -l
70214    ## files

$ find . -type d | wc -l
417      ## subdirectories