# create a test file
testfile="${HOME}/Desktop/testfile.txt"
jot -b 'sample text' 10 | cat -n > "$testfile"
printf "%s\n" >> "$testfile"                                 # add an empty line
printf "%s\n\r\n\r\n\r\r\n" "sample text" >> "$testfile"     # add lines with '\r\n' as line separators 
printf "%s" "sample text" >> "$testfile"                     # add a last line without a terminating '\n'       

open -e "$testfile"

function odcfile() {
/usr/bin/od -A n -c < "$@" | /usr/bin/sed -E -e 's/^[[:space:]]{11}//' \
       -e s/[[:space:]]{4}/$'\001'/g \
       -e 's/[[:space:]]+//g' | \
       /usr/bin/tr -d '\n' | /usr/bin/tr '\001' ' ' | \
       /usr/bin/sed -e s/\\\\n/$'\\\\\\n\\\n'/g 

return 0
}

odcfile "$testfile"



# wc -l
wc -l < "$testfile"     # returns the number of '\n' characters

# ed 
ed -s "$testfile" <<< '='     # all lines

# cat
cat -n "$testfile" | awk 'END {print $1}'   # all lines


# grep
grep -c $'\n' "$testfile"                 # all lines
grep -c '^.*$' "$testfile"                # all lines
#grep -c $'\000' "$testfile"
grep -c $'\r$' "$testfile"                # all lines ending with \r\n
grep -c '^[[:space:]]*$' "$testfile"      # all blank lines
grep -cv '^[[:space:]]*$' "$testfile"     # all non-blank lines


# sed
sed -n '$=' "$testfile"                          # all lines
sed -n /$'\r'$/= "$testfile" | wc -l             # all lines ending with \r\n
sed -n '/^[[:space:]]*$/=' "$testfile" | wc -l   # all blank lines
sed -n '/[^[:space:]]/=' "$testfile" | wc -l     # all non-blank lines


# awk
awk 'END {print NR}' "$testfile"                           # all lines
awk '{x++} END {print x}' "$testfile"                      # all lines
awk '/^.*$/ {++x} END {print x}' "$testfile"               # all lines
awk '/\r$/ {++x} END {print x}' "$testfile"                # all lines ending with \r\n
awk '/^[[:space:]]*$/ {++x} END {print x}' "$testfile"     # all blank lines
awk '/[^[:space:]]/ {++x} END {print x}' "$testfile"       # all non-blank lines


# nl
nl "$testfile" | awk 'END {print $1}'
nl -b a "$testfile" | awk 'END {print $1}'   # including empty lines


#---------------------------------------------


# counting the lines of files in a directory

DIR=/path/to/dir

find "$DIR" -type f -name "*.txt" -print0 | xargs -0 wc -l

find "$DIR" -type f -name "*.txt" -print0 | xargs -0 sed -n '$='

find "$DIR" -type f -name "*.txt" -print0 | xargs -0 awk 'END {print NR}'
find "$DIR" -type f -name "*.txt" -print0 | xargs -0 awk '{x++} END {print x}'
find "$DIR" -type f -name "*.txt" -print0 | xargs -0 awk '/\r$/ {++x} END {print x}'
find "$DIR" -type f -name "*.txt" -print0 | xargs -0 awk '/^[[:space:]]*$/ {++x} END {print x}'
find "$DIR" -type f -name "*.txt" -print0 | xargs -0 awk '/[^[:space:]]/ {++x} END {print x}'


# rather slow, but without the "Argument list too long" issue: /usr/sbin/sysctl kern.argmax
# cf. http://www.onlamp.com/pub/a/bsd/2002/03/14/FreeBSD_Basics.html

declare -i linecnt=0
while read -d $'\0' file; do
   #linecnt=$((${linecnt} + $(/usr/bin/sed -n '$=' "${file}")))
   let "linecnt += $(/usr/bin/sed -n '$=' "${file}")"   # cf. help let
done < <(/usr/bin/find "$DIR" -type f -name "*.txt" -print0)

echo $linecnt