標籤:shell計算字串長度
chars=`seq -s " " 100`;echo $chars 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100echo ${#chars}291echo $chars | wc -m292 echo $(expr length "$chars")291
time for i in $(seq 11111);do count=${#chars};done;
real 0m0.516s
user 0m0.499s
sys 0m0.017s
[[email protected] shell]# time for i in $(seq 11111);do count=`echo ${chars} | wc -m`;done;
real 0m15.773s
user 0m0.473s
sys 0m1.412s
time for i in $(seq 11111);do count=`echo exprlength "${chars}"`;done;
real 0m5.671s
user 0m0.114s
sys 0m1.856s
結論:盡量用內建功能
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shell計算字串長度方法及速度比較