Mladen, On 7/17/13 1:07 PM, Mladen Turk wrote: > On 07/17/2013 06:05 PM, sebb wrote: >> >> Why not use: >> >> if [ "$FOO" != "" ] >> > > Some shells do not allow that (comparing empty strings)
I don't know of a shell where "$FOO" would be unset and yet expand to some non-zero-length string in a command. If that were the case, ".$FOO" would then expand to the same non-zero-length string with a dot pre-pended to it and the comparison wouldn't work, anyway. In my patch, I used a "-z". I'll remove it if there is significant concern that it is very non-standard. Sebb, one reason to use the ".$FOO" trick can be found in O'Reilly's /Unix Power Tools/. They point out that by testing for "$FOO" like this: if [ "$FOO" = "somestring" ] ; You run the risk of $FOO expanding to something like "-z" where it would not result in a string comparison. I like the use of ".$FOO" (leading dot) because it avoids this issue, but I think it's moot because of the availability of the "-z" test. I couldn't find a man page online for the "test" program (but of course searching for "test man page" yields completely useless results). -chris
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