Hello-
I am doing molecular dynamics where I have to edit files. I have looked at tutorials for grep and sed but can't find my solution. The files produced in my simulations look something like this:

ATOM 1825 NE2 GLN 112 113.646 27.895 14.456
ATOM 1826 HE21 GLN 112 114.020 26.957 14.490
ATOM 1827 HE22 GLN 112 112.649 28.039 14.388
ATOM 1828 C GLN 112 116.703 32.450 16.133
ATOM 1829 O GLN 112 117.841 32.024 15.931
ATOM 1830 OXT GLN 112 116.518 33.648 16.334
TER
ATOM 1831 Na+ Na+ 113 98.608 27.104 23.903
TER
ATOM 1832 Na+ Na+ 114 90.608 27.104 29.903
TER
ATOM 1833 O WAT 115 123.924 44.364 41.207
ATOM 1834 H1 WAT 115 123.843 43.450 40.937
ATOM 1835 H2 WAT 115 123.510 44.861 40.501
TER
ATOM 1836 O WAT 116 122.056 46.142 43.088
ATOM 1837 H1 WAT 116 121.280 45.662 43.378
ATOM 1838 H2 WAT 116 122.707 45.463 42.914

and then on and on. What I want to do is get rid of the first line that has 'WAT' in it and then all the lines subsequent to that to the end of the file.

Someone suggested grep -v 'WAT' BUT that still leaves all the TER in there.

can someone tell me how to do this?

Thanks for helping a newbie

Hi, welcome to LQ!


Something like this?


Cheers,
Tink

Thanks Tink! Works great

You're welcome. Do you understand how it works?



Cheers,
Tink

I understand now- basically sed scans the lines of the file for 'WAT' as used in the delimiter /WAT/ the $ stands for the end of the file and d is for delete.

I'm afraid I'm not yet sure how to use the ,

sed isn't too hard for me with substitutions because I use vi and one often uses- e.g.- s/dd/ee/g

so I understand sed '/WAT/,d$' except the use of the comma.

Thanks for asking.

The comma is helping to define the range, ie start with first line containing WAT and go until $ (end of file)