how to trigger a mail based on first shell echo result?

Question

i have two shell scripts, one is checking_file.sh, second one is mailing.sh.

checking_file.sh

#!/bin/bash

filepath="/home/documents/hello.txt"

if [ -f "$filepath" ]; then
   echo "file exists"
else
   echo "file not exists"

fi

mailing.sh

#!/bin/bash

output=$(/home/documents/checking_file.sh)

if [ "$output" = "file not exists" ]; then
   echo "trigger mail to developer"
else
  echo "file is available in time no mail needed"
fi

mailing.sh should execute at last. both are different scripts.

i used chmod u+r+X /home/documents/checking_file.sh in mailing.sh, but mailing.sh should execute last. mailing.sh should read the checking_file.sh, its should not execute checking_file.sh shell

Answer 1

Based on OP's comments:

• mailing.sh should not call checking_file.sh but should 'read' the output from checking_file.sh
• one approach would be to have checking_file.sh write its output to a file ...
• modify checking_file.sh to write its output to a file
• modify mailing.sh to read the contents of said file

Making minimal changes to OP's current code:

$ cat checking_file.sh
#!/bin/bash

filepath="/home/documents/hello.txt"

if [ -f "$filepath" ]; then
   echo "file exists"
else
   echo "file not exists"
fi > /home/documents/checking_file.out               # write output to file



$ cat mailing.sh
#!/bin/bash

#output=$(/home/documents/checking_file.sh)
output=$(cat /home/documents/checking_file.out)      # read output from file

if [ "$output" = "file not exists" ]; then
   echo "trigger mail to developer"
else
   echo "file is available in time no mail needed"
fi

NOTES:

• OP may want to add some logic to mailing.sh to verify checking_file.out actually exists
• OP may want to add some logic to mailing.sh to remove/rename checking_file.out so that a repeated run of mailing.sh does not process the same checking_file.out a second time

---

Addressing OP's comment/question about not modifying checking_file.sh ...

With no modifications to checking_file.sh we can have the invocation direct all output to a file, eg:

$ /home/documents/checking_file.sh > /home/documents/checking_file.out 2>&1