If shell script file

I try to write a shell script but I have some difficulties to do a special if statement. I would like that if it find a value in a file it do something.

My file is like this:

1, 2, 2, 8

0, 0, 3, 3

5, 0, 4, 5

1, 4, 5, 3

1, 0, 8, 7

I do this to extract some information

sed -i '/^[0-9][0-9]*, [0-9][0-9]*, 3,/d' file.txt

But I would like to put this in a if condition, like if the third number is a 3 or 4 or 5 I do the sed else I do something else I try this:

if [ '/*, *, [3,5],/d' ]; then
    echo 'ok'
else
    echo'fail'
fi

But it doesn't wo开发者_开发问答rk, it always prints ok.

Do you know how I can do this?

please provide clearer examples next time

#!/bin/bash
# tested with bash 4
while read -r x x Y x
do
  case "$Y" in
   "3," ) echo "ok";;
   *) echo "Not ok";;
  esac
done < file

' *' will match an undetermined number of spaces. You should put [0-9]* instead.

You can use Internal-Field-Separator and let the shell take care about parsing:

#!/bin/sh
# let's create the input file
echo '5, 2, 3, 5' > /tmp/myfile

# function will output third argument
third() { IFS=', '; echo $3; }

# now let's print the third value from the input file
third $(cat /tmp/myfile)

See man sh, and look for the IFS to learn more about it.

If you are not forced to use shell-only solution you can get the third field by awk:

#!/bin/sh
THIRD=$(awk -F', ' '{print $3}' < /tmp/myfile)