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How to extract the first two characters of a string in shell scripting?
...head will give you the first two characters of the entire input
The third one uses the awk sub-string function to extract the first two characters and the fourth uses sed capture groups (using () and \1) to capture the first two characters and replace the entire line with them. They're both similar...
glob exclude pattern
...you use a glob in the directory name then you'd have a point, then at most one os.listdir() result is kept in memory as you iterate. But somepath/*.txt has to read all filenames in one directory in memory, then reduce that list down to only those that match.
– Martijn Pieters...
Can you nest html forms?
...
@Nilzor he's not asking whether or not it can't be done, he's asking WHY not. I agree; nesting forms is actually really useful. So if you have a one page app with tabs, each tab is its own form (so you can submit it to save progress), and they're all wrapped in a form, which y...
Best way to organize jQuery/JavaScript code (2013) [closed]
...ry is available.
This also has a hidden gem: the library loading will be done the second the DOM is ready, not before. This no longer halts load-up of your page!
Step 2: Modularize
See the wireframe? I have two ad units. They'll most likely have shared event listeners.
Your task in this step is ...
What's the point of map in Haskell, when there is fmap?
...
And I would further like to note, for anyone not already aware, that augustss is Lennart Augustsson, who for all practical purposes has been part of the Haskell community since before Haskell existed, cf. A History of Haskell, so the comment in question is not in an...
SQL/mysql - Select distinct/UNIQUE but return all columns?
...ach time.
On some platforms (e.g. PostgreSQL, Oracle, T-SQL) this can be done directly using window functions:
select *
from (
select *,
row_number() over (partition by field1 order by field2) as row_number
from table
) as rows
where row_number = 1
On others (MySQL, SQLite), y...
github markdown colspan
...itHub (but not on StackOverflow)
<table>
<tr>
<td>One</td>
<td>Two</td>
</tr>
<tr>
<td colspan="2">Three</td>
</tr>
</table>
Becomes
...
How to access command line arguments of the caller inside a function?
...function argv {
for a in ${BASH_ARGV[*]} ; do
echo -n "$a "
done
echo
}
function f {
echo f $1 $2 $3
echo -n f ; argv
}
function g {
echo g $1 $2 $3
echo -n g; argv
f
}
f boo bar baz
g goo gar gaz
Save in f.sh
$ ./f.sh arg0 arg1 arg2
f boo bar baz
farg2 ar...
node.js child process - difference between spawn & fork
...d is another Node command, but in this case you should use fork!) and only one copy of your node module is active on the processor.
Fork is a special instance of spawn, that runs a fresh instance of the V8 engine. Meaning, you can essentially create multiple workers, running on the exact same Node...
Check if two linked lists merge. If so, where?
...First, the numbers. Assume the first list is of length a+c and the second one is of length b+c, where c is the length of their common "tail" (after the mergepoint). Let's denote them as follows:
x = a+c
y = b+c
Since we don't know the length, we will calculate x and y without additional iterati...