I have multiple text files containing 12 lines and 3 columns.

Example:

2 6 0.74 
42 6 0.58 
80 6 0 
112 6 0.24 
132 6 1 
216 6 0.7 
342 6 0 
390 6 0.21 
432 6 0.56 
466 6 0.75 
524 6 0.6 
646 6 0.9 

I want to set all the values of the third column to 1 in all lines.

The output should look like this :

2 6 1 
42 6 1 
80 6 1 
112 6 1 
132 6 1 
216 6 1 
342 6 1 
390 6 1 
432 6 1 
466 6 1 
524 6 1 
646 6 1 

Does anyone know a command that can solve this problem?

awk 'print $1, $2, "1"' inputfile

try

awk

 awk '$3=1 ; print ;' oldfile > newfile

• 
  $3 = 1 will set third field to 1

sed (here GNU or busybox sed with its -i option for in-place editing)

sed -i 's/[0-9.]*$/1/' file

• 
  [0-9.]*$ is a sequence from 0 to 9 and . up to the end of line.

sed (golfed 4 bytes)

sed -i 's/[^ ]*$/1/' file

• 
  [^ ]*$ any char other than space, until end of line.

The lines in your expected output seem to end in two space characters and have fields separated by one tab and one space character.

If that's indeed what you want, then you'd need:

awk -v 'OFS=t ' '$3="1 "' < infile > outfile

Or with sed:

tab=$(printf 't')
sed "
 s/[[:blank:]]1,/$tab /g
 s/[^[:blank:]]1,[[:blank:]]*$/1 /
 s/^[[:blank:]]*//" < infile > outfile

Simply with GNU sed, using -i to replace text directly in the file:

sed -i 's:(.*s)(.*s)(.*):121:g' textfile

The columns are matched by regex groups in the parenthesis, reusing them with 1 and 2 and then using a "1" to replace the last group.

In this use case, the solution proposed using awk is nice and short as well.

this will do the job:

cat textfiles | cut -d' ' -f-2 | sed 's/$/ 1/'