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How to extract the first two characters of a string in shell scripting?
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Probably the most efficient method, if you're using the bash shell (and you appear to be, based on your comments), is to use the sub-string variant of parameter expansion:
pax> long="USCAGol.blah.blah.blah"
pax> short="${long:0:2}" ; echo "${short}"
US
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How to erase the file contents of text file in Python?
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In python:
open('file.txt', 'w').close()
Or alternatively, if you have already an opened file:
f = open('file.txt', 'r+')
f.truncate(0) # need '0' when using r+
In C++, you could use something similar.
sha...
Get a list of URLs from a site [closed]
...: ::::::: An error occured There was an error while accessing the URL specified: 159.121.ssss Please make sure to specify the correct website URL and resubmit your request.
– JustJohn
Jul 26 '16 at 21:29
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Error: Could not find or load main class [duplicate]
...nsure that you add the location of your .class file to your classpath. So, if its in the current folder, add . to your classpath.
Note that the Windows classpath separator is a semi-colon, i.e. a ;.
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Utility classes are evil? [closed]
... should represent a single thing and all of its attributes and operations. If you are operating on a thing, that method should probably be a member of that thing.
However, there are times when you can use utility classes to group a number of methods together — an example being the java.util.Colle...
Get current directory name (without full path) in a Bash script
... # ...useful to make hidden characters readable.
Note that if you're applying this technique in other circumstances (not PWD, but some other variable holding a directory name), you might need to trim any trailing slashes. The below uses bash's extglob support to work even with multip...
Open and write data to text file using Bash?
... the operator > redirects output to a file overwriting the file if one exists. The >> will append to an existing file.
– Rocky Pulley
May 17 '15 at 3:12
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How do I redirect in expressjs while passing some context?
I am using express to make a web app in node.js. This is a simplification of what I have:
8 Answers
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Confusion: @NotNull vs. @Column(nullable = false) with JPA and Hibernate
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Thanks! So if I want my JPA persistence not to be tied to the Hibernate implementation (i.e. change to EJB3) then I have to use both annotations (to prohibit null in both the field and its column)?
– rapt
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Why does only the first line of this Windows batch file execute but all three lines execute in a com
...new window to spawn, and each of the three commands will run in parallel. If you need them to run synchronously, use call.
– akf
Oct 27 '10 at 19:33
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