bash脚本中的if语句中期望的整数表达式

Question

我写了以下代码：

#!/bin/bash

trap 'echo "Hey your are interupting the program"' SIGINT

#function cleanup()
#{
#   echo "Cleanup called"
#   rm -rf /root/summary_command.log
#   rm -rf /root/summary_command.log
#}

#trap 'cleanup ; exit 1' EXIT SIGINT SIGILL SIGHUP

cluster_name="$(cat /home/enterprisedb/.bash_profile |grep PGCLUSTER|awk '{print $1}'|cut -d '=' -f2|cut -d ';' -f1)"
echo "$cluster_name"

wal_count=$(ls /var/lib/edb/as10/data/pg_wal/ | wc -l)
echo "$wal_count"
size_count=$(du -h /var/lib/edb/as10/data/pg_wal/|awk '{print $1}'|tail -1)
wal_size_count=$(du -sk /var/lib/edb/as10/data/pg_wal/ | awk '{ total = total + $1 } END { print total/1024**2 }')
echo "$wal_size_count"
echo "$size_count"
if [ $wal_count > 20 -a $wal_size_count < 11.0 ]; then
        echo "All working fine"
        top_file=$(expr $wal_count - 1)
        echo "$top_file"
        original_file=$(ls -lrth /var/lib/edb/as10/data/pg_wal/ |awk '{print $9}'|head -n "$top_file"|tr -d "[:space:]")
        echo "$original_file"
        su - enterprisedb << EOF
        #cp /var/lib/edb/as10/data/pg_wal/"$original_file" /u03/app/postgres/archivelog/"$cluster_name"/
EOF
else
        echo "Not working fine"
fi

if语句附近出现错误。

仅if部分无效。我也尝试过((...))和[[...]]。