Error due to unset variable - Solaris vs GNU Linux - Help needed

UNIX for Advanced & Expert Users
1

Hi all,

I have a weird problem.
When i run the below code in SunOS and Linux i get different outputs

====

$ cat tst.ksh
#!/bin/ksh
 

echo "Abc" > $LOG_FILE
echo "Ret - $?"

=====

In Solaris

$ ./tst.ksh
Abc
Ret - 0

In GNU Linux

$ ./tst.ksh
./tst.ksh[6]: : cannot open
Ret - 1

The variable LOG_FILE is not set in both environments but it works in Solaris but not in GNU Linux.

Please let me know do i need a code change in GNU environment?

thanks.

2

how does it "work" in Solaris? What does it do? What shell is that, it's terrible!

$ ksh --version
  version         sh (AT&T Research) 1993-12-28 s+
$ ksh -s <<'__EOF__'
echo "Abc" > $LOG_FILE
echo "Ret - $?"
__EOF__

ksh[1]: : cannot open
Ret - 1

bash does the same thing: bash: line 1: $LOG_FILE: ambiguous redirect

Do you really need to cover the case where LOG_FILE is unset? Perhaps write a wrapper function:

mute@thedoctor:~$ echo "Hello" > "${LOG_FILE:-/dev/null}"
mute@thedoctor:~$ echo $?
0

there, success every time. :slight_smile: