Total number of lines in a directory

Question

I have a directory with thousands of files (100K for now). When I use wc -l ./*, I\'ll get:

 c1            ./test1.txt
 c2            ./tes         


        

Answer 1

(Apologies for adding this as an answer—but I do not have enough reputation for commenting.)

A comment on @lifecrisis's answer. Perhaps cat is slowing things down a bit. We could replace cat by wc -l and then use awkto add the numbers. (This could be faster since much less data needs to go throught the pipe.)

That is

for file in *; do wc -l "$file"; done | awk '{sum += $1} END {print sum}'

instead of

for file in *; do cat "$file"; done | wc -l

(Disclaimer: I am not incorporating many of the improvements in other answers, but I thought the point was valid enough to write down.)

Here are my results for comparison (I ran the newer version first so that any cache effects would go against the newer candidate).

$ time for f in `seq 1 1500`; do head -c 5M myfile-$f |sed -e 's/\(................\)/\1\n/g'; done

real    0m50.360s
user    0m4.040s
sys 0m49.489s

$ time for file in myfile-*; do wc -l "$file"; done | awk '{sum += $1} END {print sum}'
30714902

real    0m3.455s
user    0m2.093s
sys 0m1.515s

$ time for file in myfile-*; do cat "$file"; done | wc -l
30714902

real    0m4.481s
user    0m2.544s
sys 0m4.312s