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Clear variable in python
... in that setting a variable to null in PHP gives you similar behaviour in most cases as if you hadn't defined it in the first place. A value of None in Python is quite different from an undefined variable. None is quite like most other incarnations of null, however (until we get into more arcane det...
How to tell if JRE or JDK is installed
...VA_HOME to my bash profile (.bashrc, .bash_profile, etc. depending on your OS) like below:
JAVA_HOME="/usr/lib/jvm/java-11-openjdk-amd64"
Here you go!
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Is it possible to have different Git configuration for different projects?
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The .git/config file in a particular clone of a repository is local to that clone. Any settings placed there will only affect actions for that particular project.
(By default, git config modifies .git/config, not ~/.gitconfig - only with --global does it modify the latter.)
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Postgresql: password authentication failed for user “postgres”
I have installed PostgreSQL 8.4, Postgres client and Pgadmin 3. Authentication failed for user "postgres" for both console client and Pgadmin. I have typed user as "postgres" and password "postgres", because it worked before. But now authentication is failed. I did it before a couple of times withou...
Really killing a process in Windows
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"End Process" on the Processes-Tab calls TerminateProcess which is the most ultimate way Windows knows to kill a process.
If it doesn't go away, it's currently locked waiting on some kernel resource (probably a buggy driver) and there is nothing (short of a reboot) you could do to make the proce...
Error handling in Bash
...disagree. Obviously-broken code gets noticed and fixed. Bad-practices but mostly-working code lives forever (and gets propagated).
– Charles Duffy
May 22 '14 at 16:55
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Specifying and saving a figure with exact size in pixels
...'myfig.png', dpi=1000)
Note that I used the figure dpi of 100 to fit in most screens, but saved with dpi=1000 to achieve the required resolution. In my system this produces a png with 3840x7190 pixels -- it seems that the DPI saved is always 0.02 pixels/inch smaller than the selected value, which ...
FTP/SFTP access to an Amazon S3 Bucket [closed]
...mounting entry to fstab:
<bucket> /mnt/<bucket> fuse.s3fs rw,nosuid,nodev,allow_other 0 0
For details, see my guide Setting up an SFTP access to Amazon S3.
Use S3 Client
Or use any free "FTP/SFTP client", that's also an "S3 client", and you do not have setup anything on server-si...
How do I unlock a SQLite database?
.../opened_files_view.html to find out the process is handling db file. Try closed that program for unlock database
In Linux and macOS you can do something similar, for example, if your locked file is development.db:
$ fuser development.db
This command will show what process is locking the file:...
Does Python support multithreading? Can it speed up execution time?
...he GIL to allow multiple threads of C code and one Python thread to run across multiple cores. This extends to I/O controlled by the kernel, such as select() calls for socket reads and writes, making Python handle network events reasonably efficiently in a multi-threaded multi-core setup.
What many...