#!/bin/bash -
function mytest()
{
  echo "arg1 = $1"
  if [ $1 = "1" ] ;then
    return 1
  else
    return 0
  fi
}

echo 
echo "mytest 1"
mytest 1
echo $?     # print return result

echo 
echo "mytest 0"
mytest 0
echo $?     # print return result

echo 
echo "mytest 2"
mytest 2
echo $?     # print return result


echo
echo "mytest 1 = "`mytest 1`
if mytest 1 ; then
  echo "mytest 1"
fi

echo
echo "mytest 0 = "`mytest 0`
if mytest 0 ; then
  echo "mytest 0"
fi

echo
echo "if fasle" # if 0 is error
if false; then
  echo "mytest 0"
fi


echo
mytest 1
res=`echo $?`  # get return result
if [ $res = "1" ]; then
  echo "mytest 1"
fi

echo
mytest 0
res=`echo $?`  # get return result
if [ $res = "0" ]; then
  echo "mytest 0"
fi



echo 
echo "end"

#!/bin/bash -

g_var=
function mytest2()
{
  echo "mytest2"
  echo "args $1"
  g_var=$1

  return 0
}

mytest2 1
echo "return $?"

echo
echo "g_var=$g_var"

#!/bin/bash -


function mytest3()
{
  grep "123" test.txt | awk -F: '{print $2}' | while read line ;do
    echo "$line"
    if [ $line = "yxb" ]; then
      return 0  # return to pipe only
    fi
  done

  echo "mytest3 here "
  return 1      # return to main process
}

g_var=
function mytest4()
{
  grep "123" test.txt | awk -F: '{print $2}' | while read line ;do
    echo "$line"
    if [ $line = "yxb" ]; then
      g_var=0
      echo "g_var=0"
      return 0  # return to pipe only
    fi
  done

  echo "mytest4 here "
  return 1
}

mytest3
echo $?

echo
mytest4
echo $?

echo
echo "g_var=$g_var"

#!/bin/bash 

##############################################
# Author : IT-Homer
# Date  : 2012-09-06 
# Blog  : http://blog.csdn.net/sunboy_2050
##############################################

function mytest5()
{
  grep "123" test.txt | awk -F: '{print $2}' | while read line; do
    if [ $line = "yxb" ]; then
      echo "0"  # value returned first by this function
      return 0
    fi
  done

  return 1
}

echo '$? = '"$?"
result=$(mytest5)

echo "result = $result"

echo
if [ -z $result ]    # string is null
then
  echo "no yxb. result is empyt"
else
  echo "have yxb, result is $result"
fi