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How to get the first line of a file in a bash script?
... is badly performing as the pattern space is still scanned on large files. Out of curiosity I found that 'head' wins over sed narrowly:
# best:
head -n1 $bigfile >/dev/null
# a bit slower than head (I saw about 10% difference):
sed '1q' $bigfile >/dev/null
# VERY slow:
sed -n '1p' $bigfile ...
Cron job every three days
...
Run it every three days...
0 0 */3 * *
How about that?
If you want it to run on specific days of the month, like the 1st, 4th, 7th, etc... then you can just have a conditional in your script that checks for the current day of the month.
if (((date('j') - 1) % 3))
e...
Git in Visual Studio - add existing project?
... file is this (disclaimer: this is done in Visual Studio 2013 Express, without a Team Foundation Server setup):
Open the project in Visual Studio.
Go to menu File → Add to Source Control.
That did it for me - assuming Git is set up for you, you can go to menu View → Team Explorer, then doubl...
filter for complete cases in data.frame using dplyr (case-wise deletion)
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As @jan-katins points out, the Tidyverse function is called drop_na, so you can now do: df %>% drop_na().
– cbrnr
May 16 '18 at 14:39
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WPF - How to force a Command to re-evaluate 'CanExecute' via its CommandBindings
...ere each MenuItem in the hierarchy has its Command property set to a RoutedCommand I've defined. The associated CommandBinding provides a callback for the evaluation of CanExecute which controls the enabled state of each MenuItem .
...
Check time difference in Javascript
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what's the +1 about here? What part of the date is that incrementing?
– JonnyRaa
Jun 19 '14 at 8:13
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What approaches are available to dummy design-time data in WPF?
I am working without expression blend and just using the XAML editor in vs2010. The wisdom of this aside, I am increasingly seeing a need for design-time data binding. For simple cases, the FallbackValue property works very nicely (Textboxes and TextBlocks, etc). But especially when dealing with ...
What is a good reason to use SQL views?
...LECT whatever FROM T_OLD WHERE whatever, you have two choices for the roll-out:
1) Cold Turkey - Change the DB, and at the same time, change, test and release numerous pieces of code which contained said query. VERY hard to do (or even coordinate), very risky. Bad.
2) Gradual - change the DB by cr...
Best practice for embedding arbitrary JSON in the DOM?
I'm thinking about embedding arbitrary JSON in the DOM like this:
7 Answers
7
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How do I find the location of the executable in C? [duplicate]
...("/proc/curproc/file", buf, bufsize) (FreeBSD)
readlink("/proc/self/path/a.out", buf, bufsize) (Solaris)
On Unixes without /proc (i.e. if above fails):
If argv[0] starts with "/" (absolute path) this is the path.
Otherwise if argv[0] contains "/" (relative path) append it to cwd
(assuming it hasn...