# 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

tput lines
tput cols

echo $LINES
echo $COLUMNS

stty size
stty size | awk '{print $1}'    # lines
stty size | awk '{print $NF}'   # columns

stty size | cut -d" " -f1   # lines
stty size | cut -d" " -f2   # columns 

stty -a | awk '/rows/ {print $4}'      # lines
stty -a | awk '/columns/ {print $6}'   # columns

stty -a | sed -E -n -e 's/^.*[^[:digit:]]([[:digit:]]+)[[:space:]]+rows;.*$/\1/p;q;'
stty -a | sed -E -n -e 's/^.*[^[:digit:]]([[:digit:]]+)[[:space:]]+columns;.*$/\1/p;q;'



# automatically resize the Terminal window if it gets smaller than the default size

# positive integer test (including zero)
function positive_int() { return $(test "$@" -eq "$@" > /dev/null 2>&1 && test "$@" -ge 0 > /dev/null 2>&1); }


# resize the Terminal window
function sizetw() { 
   if [[ $# -eq 2 ]] && $(positive_int "$1") && $(positive_int "$2"); then 
      printf "\e[8;${1};${2};t"
      return 0
   fi
   return 1
}


# the default Terminal window size: 26 lines and 107 columns
sizetw 26 107


# automatically adjust Terminal window size
function defaultwindow() {

   DEFAULTLINES=26
   DEFAULTCOLUMNS=107

   if [[ $(/usr/bin/tput lines) -lt $DEFAULTLINES ]] && [[ $(/usr/bin/tput cols) -lt $DEFAULTCOLUMNS ]]; then
      sizetw $DEFAULTLINES $DEFAULTCOLUMNS
   elif [[ $(/usr/bin/tput lines) -lt $DEFAULTLINES ]]; then
      sizetw $DEFAULTLINES $(/usr/bin/tput cols)
   elif [[ $(/usr/bin/tput cols) -lt $DEFAULTCOLUMNS ]]; then
      sizetw $(/usr/bin/tput lines) $DEFAULTCOLUMNS
   fi

   return 0
}


# SIGWINCH is the window change signal
trap defaultwindow SIGWINCH    


sizetw 26 70
sizetw 10 107
sizetw 4 15

export EDITOR=nano
[ctrl-x-e]   # press ctrl-x-e keys


help fc
open /usr/share/doc/bash/builtins.pdf

export FCEDIT=vim
fc     # edit last command in $FCEDIT or $EDITOR
fc -l 3 5  
fc 4     # edit command no. 4
fc -2
fc "cd "     # edit last cd command

fc -e nano     # edit last command in nano
fc -e nano "cd "
fc -e nano 4