Delete line with sed or awk (with specified condition)

Shell Programming and Scripting
1

Hello. I'm trying to delete the lines of a file does not contain the letter "T " (for example) at position 26.

So far, I could only print the result:

awk '{if (substr ($ 1,1,26)! ~ / T /) print}' file.txt

How I can do to eliminate the lines that meet this condition?

Help please. Thanks.

2

There are many many ways you could to this. With man grep (linux), for instace:

grep -v '^.........................T' inputfile

(there should be 25 ".")

With awk, I'd:

awk 'substr($0, 26, 1) != "T"' inputfile

I am sure others will come up with different methods.

1 Like
3

ready. I have it.

4 
# sed '/^.\{25\}\(T\).*/d' infile
5

That means print the lines that do, doesn't it?

awk '$26=="T"' FS= file.txt

sed '/.\{25\}T/!d' file.txt

grep '.\{25\}T' file.txt