~ $ cat log
01st line
02nd line
03rd line
04th line
05th line
06th line
07th line
08th line
09th line
10th line
11th line
12th line
13th line
14th line
15th line
~ $ echo $COLUMNS
100
~ $ tail -f log | grep --color=never 'line' | cut -c -$COLUMNS
^C
~ $ tail -f log | grep --color=never 'line'
06th line
07th line
08th line
09th line
10th line
11th line
12th line
13th line
14th line
15th line
^C
~ $ tail -f log | cut -c -$COLUMNS
06th line
07th line
08th line
09th line
10th line
11th line
12th line
13th line
14th line
15th line
^C
~ $ tail log | grep --color=never 'line' | cut -c -$COLUMNS
06th line
07th line
08th line
09th line
10th line
11th line
12th line
13th line
14th line
15th line