[SOLVED] Bash script problem "No such file or directory"
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Do you see what's happening? We're constructing a command that will look something like:
grep $grepopts $searchstring $file | sort $sortopts > $ofile
But the entire command is "hidden" in shell variables, including the I/O redirectors and various options. If the eval isn't there, this command will blow up in all sorts of bizarre ways. You'll see messages like | not found, because variable expansion occurs after output redirection. The "nested" variables (like $ofile, which is used inside of $output) won't be expanded either, so you'll also see $ofile not found. Putting an eval in front of the command forces the shell to process the line again, guaranteeing that the variables will be expanded properly and that I/O redirection will take place.
But thats your call. I just prefer to have less script to look at. Less is more.
Good luck and Regards.
You're absolutely right. That does work and is certainly more compact and also more transparent - which I certainly think is a good thing in a script. I didn't know about zcat before - pipe built in is cool.