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Bash empty array expansion with `set -u`
...iable is considered set if a subscript has been assigned a value. The null string is a valid value.
No subscript has been assigned a value, so the array isn't set.
But while the documentation suggests an error is appropriate here, this is no longer the case since 4.4.
$ bash --version | head -n ...
Command to change the default home directory of a user
...ou can also use bind-mount:
mkdir /home/username
mount --bind --verbose /extra-home/username /home/username
This is useful for allowing access "through" the /home directory to subdirs via daemons that are otherwise configured to avoid pathing through symlinks (apache, ftpd, etc.).
You have to r...
AsyncTask and error handling on Android
...ing." When you get an exception, store the exception (or some other error-string/code) in this variable. When onPostExecute is called, see if this instance-variable is set to some error. If so, show an error message." (From the user "Streets of Boston" groups.google.com/group/android-developers...
Reading a UTF8 CSV file with Python
...
The .encode method gets applied to a Unicode string to make a byte-string; but you're calling it on a byte-string instead... the wrong way 'round! Look at the codecs module in the standard library and codecs.open in particular for better general solutions for reading U...
SQL Server equivalent to MySQL enum data type?
... then you'll end-up adding lots of tables to your database. Not to mention extra IO reads due to FK constraint-checking when inserting/deleting data, whereas a CHECK CONSTRAINT is much faster and doesn't cause database object spam.
– Dai
Sep 18 at 7:23
...
Stash only one file out of multiple files that have changed with Git?
...athspec arguments' '
>foo &&
>bar &&
>extra &&
git add foo bar extra &&
git stash push -- foo bar &&
test_path_is_missing bar &&
test_path_is_missing foo &&
test_path_is_file extra &&
g...
Call Go functions from C
... as "Callbacks rock!".
fmt.Printf("%s: %d / %d (%3.2f%%)\n", userdata.(string), current, total, fc / ft)
return 0
}
This all looks a lot more complicated than it is. The call order has not changed as opposed to our previous example, but we get two extra calls at the end of the chain:
The ...
jQuery document.createElement equivalent?
...document.createElement is much faster than having jQuery convert your html string into an element. (just in case you have an urge to make things more efficient)
– Sugendran
Nov 7 '08 at 7:19
...
What's the difference between IEquatable and just overriding Object.Equals()?
...ng. The compiler can optimize away upcasts For example object o = (object)"string"; But downcasting - string s = (string)o; - must happen at runtime.
– Josh
Apr 29 '10 at 5:58
...
How do I check to see if a value is an integer in MySQL?
...
I'll assume you want to check a string value. One nice way is the REGEXP operator, matching the string to a regular expression. Simply do
select field from table where field REGEXP '^-?[0-9]+$';
this is reasonably fast. If your field is numeric, just tes...