Shell Programming and Scripting

expr: syntax error
./testdiff.sh: line 11: syntax error in conditional expression
./testdiff.sh: line 11: syntax error near `-a'
./testdiff.sh: line 11: `if [[ ${DATE_DIFF} -gt 4000 -a ${DATE_DIFF} -lt 6000 ]]'

#!/bin/bash

export CHECK_DATE_1=`date +%s`
export FILE1=/tmp/longrunmon.out

export DATE_DIFF=`expr ${CHECK_DATE_1} - ${INSERT_TIME}`

while IFS=, read INSTANCE SESS_COUNT INSERT_TIME
do

if [[ ${DATE_DIFF} -gt 4000 -a ${DATE_DIFF} -lt 6000 ]]
then
echo Critical Alert: $DATE_DIFF

elif [[ ${DATE_DIFF} -lt 600 ]]
then
echo Major Alert: $DATE_DIFF

#else
#echo not less than 600
#echo instance: $INSTANCE
#echo session_count: $SESS_COUNT
#echo date_diff: $DATE_DIFF
#echo insert_time: $INSERT_TIME
#echo check_date: $CHECK_DATE_1

fi
done < ${FILE1}

if [[ ${DATE_DIFF} -gt 4000 && ${DATE_DIFF} -lt 6000 ]]

lit-dbracm01-p002:/home/oracle>./testdiff.sh
expr: syntax error
Major Alert:
Major Alert:
lit-dbracm01-p002:/home/oracle>cat testdiff.sh
#!/bin/bash

export CHECK_DATE_1=`date +%s`
export FILE1=/tmp/longrunmon.out

export DATE_DIFF=`expr ${CHECK_DATE_1} - ${INSERT_TIME}`

DATE_DIFF=`expr 1525226185 - `

#!/bin/bash

export CHECK_DATE_1=`date +%s`
export FILE1=/tmp/longrunmon.out

#export DATE_DIFF=`expr ${CHECK_DATE_1} - ${INSERT_TIME}`

while IFS=, read INSTANCE SESS_COUNT INSERT_TIME

do

export DATE_DIFF=`expr ${CHECK_DATE_1} - ${INSERT_TIME}`

if [[ ${DATE_DIFF} -gt 4000 && ${DATE_DIFF} -lt 6000 ]]
then
echo Critical Alert: $DATE_DIFF

lit-dbracm01-p002:/home/oracle>./testdiff.sh -x
expr: syntax error
Major Alert: