Search a pattern in a line and remove another pattern

Shell Programming and Scripting
1

Hi,
I want to search a pattern in a text file and remove another pattern in that file.
my text file look like this

 0.000000  1.970000 F  303 -
1.970000  2.080000 VH VH +
2.080000  2.250000 VH VH +
2.250000  2.330000 VH L -
2.330000  2.360000 F  H +
2.360000  2.410000 L VL -
2.410000  2.450000 F  312 +

I want to search the line containing 'F' and remove signs of that line(+ or -)

2 
awk '$3=="F"{gsub(/[+-]/,X)}1' file
3

sreejith,
check it out..

$ awk '$3~/F/&&(($NF~/-/)||($NF~/\+/)){$NF="";print} ' file
0.000000 1.970000 F 303
2.330000 2.360000 F H
2.410000 2.450000 F 312
4

@reveri
He does not say that he like to remove all other line, just remove -/+ of lines with F.
Also he does not specify what part of the line does contain the F, so it does not need to be at $3

awk '/F/{NF-=1}1' file

If its at $3 and F may be in combination with other letters, use:
awk '$3~"F"{NF-=1}1' file

5

Jotne,
Thanks , understood the reqiurement now.

I tried your codes, looks like not working for me: not removing signs ( + - ) .os:hp-ux

$ awk '/F/{NF-=1}1' file
0.000000 1.970000 F 303 -
1.970000 2.080000 VH VH +
2.080000 2.250000 VH VH +
2.250000 2.330000 VH L -
2.330000 2.360000 F H +
2.360000 2.410000 L VL -
2.410000 2.450000 F 312 +

$ awk '$3~"F"{NF-=1}1' file
0.000000 1.970000 F 303 -
1.970000 2.080000 VH VH +
2.080000 2.250000 VH VH +
2.250000 2.330000 VH L -
2.330000 2.360000 F H +
2.360000 2.410000 L VL -
2.410000 2.450000 F 312 +
6

Try this:
awk '/F/{NF=NF-1}1' file
or Yodas suggestion

7

In HP-UX, you have to change NF and also force record reconstruction to get desired o/p:

awk '/F/{NF-=1;$1=$1}1' file