Shell Programming and Scripting

#!/bin/bash

pattern()
{
    if [ $1 -eq 100 ]
    then
        if [ $2 -eq 100 ]
        then
            echo debug 1
        else
            echo debug 2
        fi
    elif [ $1 -eq 50 ]
    then
        echo debug 3
    else
        echo debug 4
    fi
}

pattern 2 3

verify()
{
// do something
return $(grep -q 'VERIFICATION SUCCESSFUL' result.txt)
}

if [ verify 'a Condition' ]; then
echo debug
fi

 line 37: [: verify: unary operator expected

verify()
{
    // do something
    grep -q 'VERIFICATION SUCCESSFUL' result.txt
    if [ $? -eq 0 ]; then
        echo debug
    fi
}

pattern()
{
   val1=$1
   val2=$2
   (( val1 == 100 && val2 == 100)) && return 1
   (( val1 == 100 )) && return 2
   (( val1 == 50  )) && return 3
   return 4
}

some()
{
   input="$1"
   infile="$2"
   data=$(grep "$input"  $infile 2>/dev/null )
   stat=$?
   # if stat = 0, grep found it
   # data is empty, nothing founded or if founded, data include it
   [ "$data" = "" ] && echo "0"  && return 1
   # or
   ((stat !=0 )) &&  echo "0"  && return 1
   #
   #return passwd line
   echo "$data"
}

##############
result=$(some  "xyz"  /etc/passwd)
stat=$?
echo "stat:$stat"   # 1 if xyz not in passwd
echo "result:$result"  # 0 or passwd line
result=$(some  "root"  /etc/passwd)
stat=$?
echo "stat:$stat"   # 1 if root not in passwd
echo "result:$result"  # 0 or passwd line

pattern 100 100
echo $?
pattern 50 1
echo $?

#! /bin/bash

verify()
{
    # do something
    grep -q 'VERIFICATION SUCCESSFUL' result.txt
    verify_exit_status=$?
}

verify

if [ $verify_exit_status -eq 0 ]; then
    echo debug
fi