root@leoman-notebook:/tmp# echo 1 > /proc/sys/vm/drop_caches; echo 2 > /proc/sys/vm/drop_caches; echo 3 > /proc/sys/vm/drop_caches; sync; sync; sync
root@leoman-notebook:/tmp# time wc -l b.log
32768001 b.log

real    0m22.757s
user    0m1.532s
sys 0m1.528s
root@leoman-notebook:/tmp# echo 1 > /proc/sys/vm/drop_caches; echo 2 > /proc/sys/vm/drop_caches; echo 3 > /proc/sys/vm/drop_caches; sync; sync; sync
root@leoman-notebook:/tmp# time sed -n '$=' b.log
32768001

real    0m22.661s
user    0m7.596s
sys 0m1.332s
root@leoman-notebook:/tmp# echo 1 > /proc/sys/vm/drop_caches; echo 2 > /proc/sys/vm/drop_caches; echo 3 > /proc/sys/vm/drop_caches; sync; sync; sync
root@leoman-notebook:/tmp# time grep -n -e '$=' b.log

real    0m22.646s
user    0m4.760s
sys 0m1.212s
root@leoman-notebook:/tmp# echo 1 > /proc/sys/vm/drop_caches; echo 2 > /proc/sys/vm/drop_caches; echo 3 > /proc/sys/vm/drop_caches; sync; sync; sync
root@leoman-notebook:/tmp# time cut -c -2 b.log | wc -l
32768001

real    0m23.144s
user    0m14.069s
sys 0m1.468s
root@leoman-notebook:/tmp# echo 1 > /proc/sys/vm/drop_caches; echo 2 > /proc/sys/vm/drop_caches; echo 3 > /proc/sys/vm/drop_caches; sync; sync; sync
root@leoman-notebook:/tmp# time cut -c -1 b.log | wc -l
32768001

real    0m22.328s
user    0m14.317s
sys 0m1.364s
root@leoman-notebook:/tmp# echo 1 > /proc/sys/vm/drop_caches; echo 2 > /proc/sys/vm/drop_caches; echo 3 > /proc/sys/vm/drop_caches; sync; sync; sync
root@leoman-notebook:/tmp# time awk 'END {print NR}' b.log
32768001

real    0m22.324s
user    0m4.328s
sys 0m1.908s
root@leoman-notebook:/tmp# time cat -n b.log |awk '{print $1}'|tail -1
32768001

real    0m23.009s
user    0m24.218s
sys 0m3.356s
root@leoman-notebook:/tmp#