#
#	>	stdout
#	2>	stderr
#	&>	both stdout & stderr
#
#
# /usr/share/doc/bash-2.05b/startup-files
#
#
# Search order
# ------------
#	~/.bash_profile
#	~/.bash_login	is NOT read if .bash_profile exists ??
#	~/.profile	is NOT read if .bash_login exists ?? 
#
#
# http://www.tldp.org/LDP/Bash-Beginners-Guide/html/sect_03_01.html
#
# (generic) /etc/profile is read when:
#	bash --login  
#	sh foo.sh
#	csh foo.csh
#	ksh foo.ksh
#
# ~/.bashrc
#	if [ -f /etc/bashrc ]; then
#	      . /etc/bashrc
#	fi
#
#	set -o noclobber
#
#
# ~/.bash_profile
#	source ~/.bashrc
#	source ~/.bash_login
# 
# ~/.bash_login
#	umask 002
#
# ~/.login
#
#
# ~/.bash_logout
# ~/.logout
#
# http://www.tldp.org/LDP/Bash-Beginners-Guide/html/sect_03_01.html
#	variables are NOT inherited by child processes
#	unless they are exported by the parent shell
#
#	sourcing a file applies changes and setting variables in the current shell
#
#
# Variables are case sensitive
# ----------------------------
# 
# env or printenv
# -----------------
#	Global variables or environment variables are available in all shells
#	( and must be exported ?? )
#
#
# "set LocalVar" to define local variables
# ----------------------------------------
#	Local variables are only available in the current shell
#
#
#	to see what is set on or off
#		"set -o"
#
#
# Compare Global variables vs local variables
# --------------------------------------------
#	set | sort > set.sorted
#	printenv | sort >  printenv.sorted
#	diff set.sorted printenv.sorted | grep "<" | awk '{ print $2 }'
#
#
# Exported Variables
# ------------------
#	http://www.tldp.org/LDP/Bash-Beginners-Guide/html/sect_03_02.html
#
#	A subshell can change variables it inherited from the parent,
#	but the changes made by the child don't affect the parent ( even if it's exported ?? )
#
#
# IFS is "'<space><tab><newline>'", the default used as delimiters
#	http://www.tldp.org/LDP/Bash-Beginners-Guide/html/sect_03_04.html
#
#
#
date +"%y%m%d_%H%M%S" 	031128_214136
#
# Advanced bash scripting
http://www.tldp.org/LDP/abs/html
#
#
http://www.uwsg.iu.edu/UAU/shell/script/test.html
http://www.uwsg.iu.edu/UAU/shell/script/trap.html
http://www.ussg.iu.edu/UAU/shell/script/control.html
#
http://www.bagley.org/~doug/shootout/lang/bash/allsrc.shtml
#
http://www.linux.se/doc/HOWTO/Adv-Bash-Scr-HOWTO/external.html
#
http://www.introcomp.co.uk/scripts
#
#
#
# Check if $DEST responds
#
Alive=`ping -s 1 -c 1 $DEST > /dev/null; echo $?`
#
if [ $Alive -eq 0 ]; then
    echo "$DEST is alive"
else
    echo "$DEST is offline"
fi
#
# ------------------------------------------------------
#
# test -d /etc/init.d/SAVE || mkdir /etc/init.d/SAVE
#	
# if [ ! -d foo ];
# then
#	mkdir foo
# elif [ soemthing else ];
# then
#	do that
# fi
#
function Ack () {
    if [ $1 -eq 0 ]; then
        Ack=$[ $2 + 1 ]
    elif [ $2 -eq 0 ]; then
        Ack $[ $1 - 1 ] 1
    else
        Ack $1 $[ $2 - 1 ]
        local SubAck=$Ack
        Ack $[ $1 - 1 ] $SubAck
    fi
}
#
#
n=${1:-1}
Ack 3 $n
echo "Ack(3,$n): $Ack"
#
#
#
function fib {
    if [ $1 -lt 2 ] ; then
        echo 1
    else
        echo $[ `fib $[ $1 - 2 ]` + `fib $[ $1 - 1 ]` ]
    fi
}

N=${1:-1}
fib $N
#
#
#
#
#!/bin/sh
#
# in case things dont expand
#
shopt -s nullglob

if [ -n "$(echo /tmp/*.{jpg,JPG,jpeg,JPEG})" ]; then
        echo "Files exist"
else
        echo "Files do not exist"
fi
#
#
        foo=1
        while [ $foo -lt 3 ]; do
                echo "foo is $foo"
                foo=$(( foo + 1))
        done
        echo "final foo is $foo"

results in this output

        foo is 1
        foo is 2
        final foo is 3

#
#
#
#!/bin/bash
set -x	# echo all commands executed
set -v
#
for i in 1 2 3 4 5;
do
    echo foobar${i} ;
done
#
#
#
ls | while read file
do
        ls -la 
done
#
#
# 
RSYNC_COMMAND="rsync /html/ webmaster@second_server:/html/ -e ssh -r --delete --times --modify-window=1 --exclude /serverid.html"

$RSYNC_COMMAND -n -v
#
while echo -n "Proceed with sync ?(y/n)"
read response
do
  case "$response" in
  'n')  echo "Syncronization cancelled"
        break
                       ;;
  "y")  $RSYNC_COMMAND -v
        echo "Syncronization completed"
        break
                       ;;
  esac
done
#
#
# end of file