CODEWITHSUNDEEP
linuxunix
Jannat Arora
Jannat Arora

Reputation: 2989

To remove undesired lines using linux command

I have a csv file(1TB) of the following form:

 1     hi hello
 2     users badges
 abc def
 3     questions
 4     tags
 Unanswered answered

Whenever I have a string in the beginning of the line, I want to delete that line and whenever I have a number(integer) in the beginning of the line I want to retain that line. I want the output in the following format:

 1     hi hello
 2     users badges
 3     questions
 4     tags

Is it possible to achieve it using a linux command. I know it is possible to achieve this using a programming language like python but is it possible to achieve using cat and sed, etc

Upvotes: 0

Views: 74

Answers (2)

mau
mau

Reputation: 258

sed '/^[^0-9].*/d' test.txt

That deletes any lines that don't start with 0-9 in file test.txt

Upvotes: 2

falsetru
falsetru

Reputation: 368904

Using grep to filter lines:

$ cat > a_file
 1     hi hello
 2     users badges
 abc def
 3     questions
 4     tags
 Unanswered answered
$ grep '^ *[0-9]' a_file > a_file.modified
$ cat a_file.modified
 1     hi hello
 2     users badges
 3     questions
 4     tags
$ mv a_file.modified a_file

Upvotes: 0

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