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How to check if a process id (PID) exists
...will have a race condition.
If you want to ignore the text output of kill and do something based on the exit code, you can
if ! kill $pid > /dev/null 2>&1; then
echo "Could not send SIGTERM to process $pid" >&2
fi
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What do 'real', 'user' and 'sys' mean in the output of time(1)?
What do 'real', 'user' and 'sys' mean in the output of time?
6 Answers
6
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What should every programmer know about security? [closed]
I am an IT student and I am now in the 3rd year in university. Until now we've been studing a lot of subjects related to computers in general (programming, algorithms, computer architecture, maths, etc).
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Detecting iOS / Android Operating system
I've done some research, and this question has come up, but not in the way I intend. I'm building a page for a client that is a QR code landing, which is a place to download an application. So he doesn't have to print out 2 QR codes on a page, I'd like to detect the current operating system (Apple...
Copy a file in a sane, safe and efficient way
... std::ios::binary);
dst << src.rdbuf();
}
This is so simple and intuitive to read it is worth the extra cost. If we were doing it a lot, better to fall back on OS calls to the file system. I am sure boost has a copy file method in its filesystem class.
There is a C method for intera...
What kind of virtual machine is BEAM (the Erlang VM)?
From what I understand a virtual machine falls into two categories either "system virtual machine" or a "process virtual machine". It's kind of fuzzy to me where BEAM lies. Is there another kind of virtual machine I am not aware of?
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How can I explicitly free memory in Python?
... I'm using python 3.6. Calling gc.collect() after loading a pandas dataframe from hdf5 (500k rows) reduced memory usage from 1.7GB to 500MB
– John
Jan 18 '18 at 20:30
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How to upgrade PostgreSQL from version 9.6 to version 10.1 without losing data?
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Assuming you've used home-brew to install and upgrade Postgres, you can perform the following steps.
Stop current Postgres server:
launchctl unload ~/Library/LaunchAgents/homebrew.mxcl.postgresql.plist
Initialize a new 10.1 database:
initdb /usr/local/var/postgre...
Best way to determine user's locale within browser
I have a website (Flash) localized into a dozen of languages and I want to auto-define a default value depending on the user's browser settings in order to minimize the steps to access the content.
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Search and replace in bash using regular expressions
...is method, i.e. perl, awk, e.g.:
echo "$MYVAR" | perl -pe 's/[a-zA-Z]/X/g and s/[0-9]/N/g'
This may allow you to do more creative matches... For example, in the snip above, the numeric replacement would not be used unless there was a match on the first expression (due to lazy and evaluation). A...