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What's a concise way to check that environment variables are set in a Unix shell script?
...(an empty string) is OK — not exactly what you want, but the alternative and older notation.
The second variant (using :?) requires DEST to be set and non-empty.
If you supply no message, the shell provides a default message.
The ${var?} construct is portable back to Version 7 UNIX and the Bourne ...
cscope or ctags why choose one over the other? [closed]
I primarily use vim / gvim as an editor and am looking at using a combination of lxr (the Linux Cross Reference) and either cscope or ctags for exploring the kernel source. However, I haven't ever used either cscope or ctags and would like to hear why one might choose one over the other t...
How to find list of possible words from a letter matrix [Boggle Solver]
...ictionary word that could be a solution must use only the grid's
# letters and have length >= 3. (With a case-insensitive match.)
import re
alphabet = ''.join(set(''.join(grid)))
bogglable = re.compile('[' + alphabet + ']{3,}$', re.I).match
words = set(word.rstrip('\n') for word in open('words')...
SQL order string as number
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and if you have mixed string and number and want them both sorted, use "order by col * 1, col"
– Hayden Thring
Feb 23 '15 at 3:42
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Elegant ways to support equivalence (“equality”) in Python classes
...om classes it is often important to allow equivalence by means of the == and != operators. In Python, this is made possible by implementing the __eq__ and __ne__ special methods, respectively. The easiest way I've found to do this is the following method:
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Bad class file magic or version
I already know that question has been already asked very often and answers, but no one of the answers i found fixed my problem.
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Regex - how to match everything except a particular pattern
...particular pattern? I'm faced with a situation where I have to match an (A and ~B) pattern.
8 Answers
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npm install vs. update - what's the difference?
What is the practical difference between npm install and npm update ? When should I use which?
5 Answers
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Keep file in a Git repo, but don't track changes
...t solution to do this. First change the file you do not want to be tracked and use the following command:
git update-index --assume-unchanged FILE_NAME
and if you want to track the changes again use this command:
git update-index --no-assume-unchanged FILE_NAME
git-update-index documentation...
How do I use prepared statements in SQlite in Android?
How do I use prepared statements in SQlite in Android?
5 Answers
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