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What is the difference between $(command) and `command` in shell programming?
... for portability issues it is recommended to use backticks for non-nested calls. $(...) needs a recursive parser but this was not used with ksh86 that introduced the feature. Check in-ulm.de/~mascheck/various/cmd-subst for a list of correct implementations. A conforming shell needs to support all c...
How to redirect output to a file and stdout
In bash, calling foo would display any output from that command on the stdout.
10 Answers
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Why are Docker container images so large?
I made a simple image through Dockerfile from Fedora (initially 320 MB).
8 Answers
8
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C++ - passing references to std::shared_ptr or boost::shared_ptr
...now that sp->do_something() will not blow up due to a null pointer?
It all depends what is in those '...' sections of the code. What if you call something during the first '...' that has the side-effect (somewhere in another part of the code) of clearing a shared_ptr to that same object? And wha...
Is there a naming convention for Django apps
...-app" would be a syntax error). PEP 8 says:
Modules should have short, all-lowercase names. Underscores can be used
in the module name if it improves readability. Python packages should
also have short, all-lowercase names, although the use of underscores is
discouraged.
So, 1 and 3 ar...
get NSDate today, yesterday, this Week, last Week, this Month, last Month… variables
...ve the seconds into the day if you want
NSDate *today = [NSDate date];
// All intervals taken from Google
NSDate *yesterday = [today dateByAddingTimeInterval: -86400.0];
NSDate *thisWeek = [today dateByAddingTimeInterval: -604800.0];
NSDate *lastWeek = [today dateByAddingTimeInterval: -1209600.0]...
Difference between volatile and synchronized in Java
...om obtaining the monitor (or lock) for the same object, thereby preventing all code blocks protected by synchronization on the same object from executing concurrently. Synchronization also creates a "happens-before" memory barrier, causing a memory visibility constraint such that anything done up t...
How to select all records from one table that do not exist in another table?
...e = t1.name
WHERE t2.name IS NULL
Q: What is happening here?
A: Conceptually, we select all rows from table1 and for each row we attempt to find a row in table2 with the same value for the name column. If there is no such row, we just leave the table2 portion of our result empty for that row. The...
Can constructors throw exceptions in Java?
Are constructors allowed to throw exceptions?
6 Answers
6
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How do I delete NuGet packages that are not referenced by any project in my solution?
...h the new version. They each have only a Manage button -- but no uninstall button. And when you look to see where they are used, you can see that they are referenced by none of the solution's projects? They are NOT displaying an Uninstall?
...