CODEWITHSUNDEEP
unixawkgrepfind
ThePerson
ThePerson

Reputation: 3236

Unix - Find patterns in file, copy into another file

I have spent some time considering how to tackle this but i'm not sure and my use of unix is fairly limited so far.

I have a text file, lets give it a name "Text.txt", which contains lots of information. Let's say it contains:

SomethingA: aValue
SomethingB: bValue
SomethingC: cValue
SomethingD: dValue
SomethingD: anotherDValueThisTime
SomethingA: aValueToIgnore

I want to search through "Text.txt", and find some values, then put the values in a new file, output.txt.

This gets a little bit more tricky tough, as what I am trying to do is get the first value of somethingA, and then every SomethingD value which occurs.

So the output in "output.txt" should be:

aValue
dValue
anotherDValue

The second "SomethingA" value wants to be ignored as this is not the first "SomethingA" value.

I imagine the logic to be something like: Find SomethingA > output.txt Find ALL SomethingD's >> output.txt

But I just can't quite get it. Any help is much appreciated!

Upvotes: 1

Views: 9653

Answers (3)

manishmadhukar
manishmadhukar

Reputation: 1

I think what you need is the grep command with the -o options. It works like this:

grep -o -e 'pattern1' -e 'pattern2' /tmp/1 >> /tmp/2

Upvotes: 0

Stobor
Stobor

Reputation: 45122

grep -m 1 somethingA inputfile.txt >outputfile.txt
grep somethingD inputfile.txt >>outputfile.txt

grep option -m sets the maximum number of matches you want to get.

>> appends to a file rather than overwriting it like > does.

Upvotes: 1

William Pursell
William Pursell

Reputation: 212248

awk is ideal

awk '/^SomethingA/ && ! a++ || /^SomethingD/ { print $2 }' FS=: text.txt > output.txt

This is a little sloppy, but you can be more precise with:

awk '$1 == "SomethingA" && ! a++ || $1 == "SomethingD" { print $2 }' FS=: text.txt > output.txt

Unfortunately, that requires a fixed string for the keys. If you want a regex, you can do:

awk 'match($1, "pattern") && ...

Upvotes: 2

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