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linuxbashcentosredhat

A mismatch between CENTOS 7 and Red Hat Enterprise Linux Server release 6.7

I have a bash script, it works on CENTOS fine, but when I want to run the script on Red Hat Enterprise Linux, I got the following error.

if [ "${line:(-2)}" == "nm" ]
 then
sub_sh=${line:31:8}
if [ $sub_sh != "test" ];
  then
sub_str=${line:0:10}
date_line=$(date --date=$sub_str '+%Y%m%d')
result=`expr $date_line - $yesterday`
if [ $result  -gt 1000 ];
then
 Rtime="${line##* }"
 pureqrt=${Rtime::-2}  #line 56

Error:

line 56: -2: substring expression < 0
Solution

  • I used the below script to remove the two last characters

    #   in bash
#   pureqrt=${queryRtime::-2}
    pureqrt=$(echo $queryRtime | cut -d "m" -f 1)
----------------------------------------------
#command line 
 echo "2234ms" | cut -d "m" -f 1
 output : 2234

    I appreciate your help