Question

Write a short script filecount.sh that counts the total number of files in the current directory with names matching a specified pattern, and print out this number to screen. For example,

bash filecount.sh *.txt

should return the number of .txt files found in the current directory, while

bash filecount.sh p*.txt

should return the number of text files with names starting with p.

Answer 1

1. return the number of .txt files found in the current directory

the script:

#!/bin/bash

START=$HOME
# change your directory to command line if passed
# otherwise use home directory
[ $# -eq 1 ] && START=$1
if [ ! -d $START ]
then
   echo "$START not a directory!"
   exit 1
fi
# use find command to get all subdirs name in DIRS variable
DIRS=$(find "$START" -type d)
# loop thought each dir to get the number of files in each of subdir
for d in $DIRS
do
   [ "$d" != "." -a "$d" != ".." ] && echo "$d dirctory has $(ls -l $d | wc -l) files"
done

2. should return the number of text files with names starting with p.

set -- *p* ; echo "$#"                             # change positional arguments

count=$(printf 'x%.0s' *p*); echo "${#count}"      # most shells

printf -v count 'x%.0s' *p*; echo "${#count}"      # bash