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Number of processors/cores in command line
...d you give is the most portable on Linux. Instead of spawning unnecessary cat and wc processes, you can shorten it a bit:
$ grep --count ^processor /proc/cpuinfo
2
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How to pass the value of a variable to the stdin of a command?
..."$blah"? With that one change (avoiding the many pitfalls in echo's specification, which Stephane's excellent answer goes into in detail at Why is printf better than echo? on Unix & Linux, or which the APPLICATION USAGE section of the echo specification touches on more briefly) it's a perfectly ...
Mean per group in a data.frame [duplicate]
...53 19
Ben 2 22 87
Ben 3 19 45
Cat 1 22 87
Cat 2 67 43
Cat 3 45 32', header=TRUE)
aggregate(d[, 3:4], list(d$Name), mean)
Group.1 Rate1 Rate2
1 Aira 16.33333 47.00000
2 Ben 31.33333 ...
Open and write data to text file using Bash?
...
#!/bin/sh
FILE="/path/to/file"
/bin/cat <<EOM >$FILE
text1
text2 # This comment will be inside of the file.
The keyword EOM can be any text, but it must start the line and be alone.
EOM # This will be also inside of the file, see the space in front of...
How can I represent an 'Enum' in Python?
...enum import Enum # for the aenum version
Animal = Enum('Animal', 'ant bee cat dog')
Animal.ant # returns <Animal.ant: 1>
Animal['ant'] # returns <Animal.ant: 1> (string lookup)
Animal.ant.name # returns 'ant' (inverse lookup)
or equivalently:
class Animal(Enum):
ant = 1
b...
What is the difference between up-casting and down-casting with respect to class variable
...ClassCastExceptions:
Animal animal = getAnimal(); // Maybe a Dog? Maybe a Cat? Maybe an Animal?
if (animal instanceof Dog) {
// Guaranteed to succeed, barring classloader shenanigans
Dog castedDog = (Dog) animal;
}
...
Split string into array of character strings
...
"cat".split("(?!^)")
This will produce
array ["c", "a", "t"]
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How can I copy the output of a command directly into my clipboard?
...
You can then pipe the output into xclip to be copied into the clipboard:
cat file | xclip
To paste the text you just copied, you shall use:
xclip -o
To simplify life, you can set up an alias in your .bashrc file as I did:
alias "c=xclip"
alias "v=xclip -o"
To see how useful this is, imagin...
List all indexes on ElasticSearch server?
...ie" : {
"aliases" : {
"rumpleteazer" : { },
"that_horrible_cat" : { }
}
}
}
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Can linux cat command be used for writing text to file?
...
Sounds like you're looking for a Here document
cat > outfile.txt <<EOF
>some text
>to save
>EOF
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