Cheatsheet: Difference between revisions
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#Client sends the second half of the Diffie-Hellman exchange, Computes the session keys; Switches to encrypted communication
#Server computes the session keys; Switches to encrypted communication.
<br>
; SSLv1 vs TLS 1.0 vs TLS1.3
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ls > file.log 2>&1 OR ls &> file.log
ls > file.log 2> /dev/null
=== System Calls ===
{{UC}}
= Sorting Algorithms =
It is a good default choice.
It tends to be fast in
* Heapsort
The Linux kernel uses heapsort instead of quicksort for both of those reasons.▼
where the bottleneck cost is reading and writing the input on disk, not comparing and swapping individual items.▼
* Merge sort
'''Radix sort''' looks fast, with its O(n)O(n)O(n) worst-case time complexity. ▼
It is a good choice if you want a stable sorting algorithm.
if you're using it to sort binary numbers, then there's a hidden constant factor that's usually 32 or 64 (depending on how many bits your numbers are).▼
▲ It can easily be extended to handle data sets that can't fit in
That's often way bigger than O(lg(n))O(\lg(n))O(lg(n)), meaning radix sort tends to be slow in practice.▼
'''Counting sort''' is a good choice in scenarios where there are small number of distinct values to be sorted. ▼
* Radix sort
This is pretty rare in practice, and counting sort doesn't get much use.▼
▲
▲
* Counting sort
▲
* Which sorting algorithm has best asymptotic run time complexity?
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(output, err) = p.communicate()
print("Today is", output)
= SMTP =
HELO or EHLO (Hello)
MAIL FROM
250 OK reply code
RCPT TO (Recipient To)
250 OK reply code
DATA
345 reply code
250 OK code
QUIT
221 code
RSET (Reset)
SMTP errors:
4.X.X Persistent Transient Failure
5.X.X Permanent Error:
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