cut: get either one or two fields

Shell Programming and Scripting
1

Hello,

I would like to extract one or two fields of a line.

At the moment, I am extracting the first field of a line:

command | cut -f 1 -d '.' > file

The line can have two or three fields delimited with a dot.

if three fields, I want to be able to get the first two
ie if line = X.Y.Z
output X.Y
if two fields, I want to be able to get the first one only.
ie if line = X.Y
output X

How can I do this ?

Thank you for any help
Max

2 
#!/usr/bin/ksh

NOF=`echo $1 | awk -F. '{ print NF}'` 
case $NOF in
2)
echo $1 | awk -F. '{ print $1}'
;;
3)
echo $1 | awk -F. '{ print $1 "." $2}'
;;
esac

or

[[ `echo $1 | awk -F. '{ print NF}'` -eq "2" ]] && print $1 | awk -F. '{ print $1}' || print $1 | awk -F. '{ print $1 "." $2}'
3 
printf "%s\n" "${line%.*}"

I mean:

$ printf "X.Y.Z\n"|while IFS= read -r;do printf "%s\n" "${REPLY%.*}";done
X.Y
$ printf "X.Y\n"|while IFS= read -r;do printf "%s\n" "${REPLY%.*}";done
X

If you read doesn't support the -r switch, remove it.

If your shell support process substitution:

$ { read;printf "${REPLY%.*}";}< <(printf "X.Y.Z\n")
X.Y
$ { read;printf "${REPLY%.*}";}< <(printf "X.Y\n")
X

Where the second printf is your command.

4

Thank you for your answers !
It fixes my problem

Max