CODEWITHSUNDEEP
shellunix
Vikas
Vikas

Reputation: 127

Return negative in Unix Shell Script Functions

in a script, I am returning negative integer from a function. I one envrionment with Bash Version : GNU bash, version 3.2.51(1)-release (x86_64-suse-linux-gnu) the script is running

and in other envrionment with Bash Version : GNU bash, version 4.2.46(2)-release (x86_64-redhat-linux-gnu) the script is not running and it terminates as soon as it gets return -1008 in a function. when I am trying to return positive integer instead of negative, its working fine.

I am not sure whether this is because the bash version difference. but what could be the issue ?

return -1008

Upvotes: 1

Views: 3008

Answers (2)

Walter A
Walter A

Reputation: 20002

Return a value with an echo when you don't write other things to stdout:

exists_hdfs_folder()
{
   local folder=$1
   # info "Checking if \"${folder}\" exists in hdfs.... "
   hadoop fs -test -d $folder 2>&1 > /dev/null
   if [ "$?" -eq "$OK" ]; then 
      # info "HDFS FOLDER EXISTS - folder:${folder}"
      echo "$OK"
   else
      # info "HDFS FOLDER DOES NOT EXIST - folder:${folder}"
      echo "$ERROR_GENERIC_HDFS_FOLDER_NOT_EXISTS"
      # offtopic: Better lowercase and braces like
      # echo "${error_generic_hdfs_folder_not_exists}"
   fi 
}

And call that function with

returnvalue=$(exists_hdfs_folder)

I commented the info function, it might write to stdout. When you do want functions writing to stdout, you might use a variable

exists_hdfs_folder()
{
   local folder=$1
   # global
   retval_exists_hdfs_folder="-99"

   info "Checking if \"${folder}\" exists in hdfs.... "
   hadoop fs -test -d $folder 2>&1 > /dev/null
   if [ "$?" -eq "$OK" ]; then 
      info "HDFS FOLDER EXISTS - folder:${folder}"
      retval_exists_hdfs_folder="$OK"
      return 0
   else
      info "HDFS FOLDER DOES NOT EXIST - folder:${folder}"
      retval_exists_hdfs_folder="${error_generic_hdfs_folder_not_exists}"
      return 1
   fi 
}

And call that function with

exists_hdfs_folder || { echo "Failure: ${retval_exists_hdfs_folder}"; }

Upvotes: 0

William Pursell
William Pursell

Reputation: 212248

Return values are generally modulo 256:

#!/bin/sh
foo() { printf "Return $1: "; return $1; }

foo -5; echo $?
foo 300; echo $?
$ ./a.sh
Return -5: 251
Return 300: 44

Upvotes: 2

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