CODEWITHSUNDEEP
stringbashcomparison
Justin S
Justin S

Reputation: 1459

bash string comparison not working although code appears fine

Below is my simple bash script

!/usr/bin/sh
cmd_output=$(ctmcontb -ADD $2 $3)
echo below is the hex output of "CONDITION:${2} DATE:${3} added"
echo "CONDITION:${2} DATE:${3} added" | od -xc
echo below is the hex output for the variable cmd_ouput
echo "$cmd_output" | od -xc
echo raw input passed to cmdlet with user arguments inputted and a space added infront
echo " CONDITION:${2} DATE:${3} added" | od -xc
if [ "$cmd_ouput" = " CONDITION:${2} DATE:${3} added" ]; then
        echo successfull ran util
        exit 0
else
        echo error occurred running util
        exit 1
fi

Below is the output

ctmtest1-tctmsv80 [49] job_late.sh ctmtest1 u350932-14 0910
below is the hex output of CONDITION:u350932-14 DATE:0910 added
0000000     434f    4e44    4954    494f    4e3a    7533    3530    3933
           C   O   N   D   I   T   I   O   N   :   u   3   5   0   9   3
0000020     322d    3134    2044    4154    453a    3039    3130    2061
           2   -   1   4       D   A   T   E   :   0   9   1   0       a
0000040     6464    6564    0a00
           d   d   e   d  \n
0000045
below is the hex output for the variable cmd_ouput
0000000     2043    4f4e    4449    5449    4f4e    3a75    3335    3039
               C   O   N   D   I   T   I   O   N   :   u   3   5   0   9
0000020     3332    2d31    3420    4441    5445    3a30    3931    3020
           3   2   -   1   4       D   A   T   E   :   0   9   1   0
0000040     6164    6465    640a
           a   d   d   e   d  \n
0000046
raw input passed to cmdlet with user arguments in putted and a space added in front
0000000     2043    4f4e    4449    5449    4f4e    3a75    3335    3039
               C   O   N   D   I   T   I   O   N   :   u   3   5   0   9
0000020     3332    2d31    3420    4441    5445    3a30    3931    3020
           3   2   -   1   4       D   A   T   E   :   0   9   1   0
0000040     6164    6465    640a
           a   d   d   e   d  \n
0000046
error occurred running util

So as you can see the string comparison line 

if [ "$cmd_ouput" = " CONDITION:${2} DATE:${3} added" ]; then

doesn't appear to successfully compare the strings even though they are from what I can see the same.

I noticed there was a space added to the raw input after it is run through the cmdlet. So to combat this I basically added a space manually in the string comparison (I know not the greatest way of doing it but I ran out of ideas)

Basically im not sure why the string comparison is not working when the strings are the same and my bash code appears correct?

Upvotes: 0

Views: 86

Answers (1)

Chris Beck
Chris Beck

Reputation: 16204

This version appears to work?

Here was my code.

ctmcontb:

#!/bin/bash
echo " CONDITION:${2} DATE:${3} added"

test2.sh:

#!/bin/bash
cmd_output=$(./ctmcontb -ADD "$2" "$3")
expected=" CONDITION:${2} DATE:${3} added"
echo below is the hex output of "CONDITION:${2} DATE:${3} added"
echo "CONDITION:${2} DATE:${3}" | od -xc
echo below is the hex output for the variable cmd_ouput
echo "$cmd_output" | od -xc
echo raw input passed to cmdlet with user arguments inputted and a space added infront
echo "${expected}" | od -xc
if [ "${cmd_ouput}"="${expected}" ]
then
        echo successfull ran util
        exit 0
else
        echo error occurred running util
        exit 1
fi

Alternately, something like this, based on return codes instead of the exact returned string, seems a lot simpler and more consistent with the rest of unix, even if it requires changing the ctmcontb program a bit:

ctmcontb

#!/bin/bash
if [[ "$1" -eq 1 ]]; then
  exit 0
else
  exit 1
fi

test.sh

#!/bin/bash
./ctmcontb "$1"
result="$?"
if [[ result -eq 0 ]]; then
  echo "Success"
  exit 0
else
  echo "Fail"
  exit 1
fi


$ ./test3.sh 2
Fail
$ ./test3.sh 1
Success
$ ./test3.sh 0
Fail

Upvotes: 1

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