find使用xargs和exec执行效率比较
在linux上测试在使用find命令进行批量操作时，xargs和exec两种方式那个效率更高。
目的
在linux上测试在使用find命令进行批量操作时，xargs和exec两种方式那个效率更高。
实验
实验准备
批量创建一批文件，用来做测试使用
# 创建100个文件
[root@localhost a]# touch file{1..100}
[root@localhost a]# ls
file1 file13 file18 file22 file27 file31 file36 file40 file45 file5 file54 file59 file63 file68 file72 file77 file81 file86 file90 file95
file10 file14 file19 file23 file28 file32 file37 file41 file46 file50 file55 file6 file64 file69 file73 file78 file82 file87 file91 file96
file100 file15 file2 file24 file29 file33 file38 file42 file47 file51 file56 file60 file65 file7 file74 file79 file83 file88 file92 file97
file11 file16 file20 file25 file3 file34 file39 file43 file48 file52 file57 file61 file66 file70 file75 file8 file84 file89 file93 file98
file12 file17 file21 file26 file30 file35 file4 file44 file49 file53 file58 file62 file67 file71 file76 file80 file85 file9 file94 file99
# 修改前50个文件的文件属主和属组为jin
[root@localhost a]# chown jin:jin file{1..50}
[root@localhost a]# ll |head -10
total 0
-rw-r--r--. 1 jin jin 0 Jul 19 11:02 file1
-rw-r--r--. 1 jin jin 0 Jul 19 11:02 file10
-rw-r--r--. 1 root root 0 Jul 19 11:02 file100
-rw-r--r--. 1 jin jin 0 Jul 19 11:02 file11
-rw-r--r--. 1 jin jin 0 Jul 19 11:02 file12
-rw-r--r--. 1 jin jin 0 Jul 19 11:02 file13
-rw-r--r--. 1 jin jin 0 Jul 19 11:02 file14
-rw-r--r--. 1 jin jin 0 Jul 19 11:02 file15
-rw-r--r--. 1 jin jin 0 Jul 19 11:02 file16
time命令
time命令用来统计一个命令执行使用的时间
语法：time + 执行的命令
实例：
[root@localhost a]# time ls
file1 file13 file18 file22 file27 file31 file36 file40 file45 file5 file54 file59 file63 file68 file72 file77 file81 file86 file90 file95
file10 file14 file19 file23 file28 file32 file37 file41 file46 file50 file55 file6 file64 file69 file73 file78 file82 file87 file91 file96
file100 file15 file2 file24 file29 file33 file38 file42 file47 file51 file56 file60 file65 file7 file74 file79 file83 file88 file92 file97
file11 file16 file20 file25 file3 file34 file39 file43 file48 file52 file57 file61 file66 file70 file75 file8 file84 file89 file93 file98
file12 file17 file21 file26 file30 file35 file4 file44 file49 file53 file58 file62 file67 file71 file76 file80 file85 file9 file94 file99
real 0m0.006s
user 0m0.002s
sys 0m0.004s
xargs测试
#删除当前目录下文件属主为jin的文件
[root@localhost a]# time find ./ -user jin |xargs rm -rf
real 0m0.006s
user 0m0.001s
sys 0m0.005s
[root@localhost a]# ls
file100 file53 file56 file59 file62 file65 file68 file71 file74 file77 file80 file83 file86 file89 file92 file95 file98
file51 file54 file57 file60 file63 file66 file69 file72 file75 file78 file81 file84 file87 file90 file93 file96 file99
file52 file55 file58 file61 file64 file67 file70 file73 file76 file79 file82 file85 file88 file91 file94 file97
可以看到使用管道配置xargs查找并删除文件属主为jin的文件一共用时0.006s,前50个文件已经被删除
exec测试
#创建file1...file50文件
[root@localhost a]# touch file{1..50}
[root@localhost a]# ls
file1 file13 file18 file22 file27 file31 file36 file40 file45 file5 file54 file59 file63 file68 file72 file77 file81 file86 file90 file95
file10 file14 file19 file23 file28 file32 file37 file41 file46 file50 file55 file6 file64 file69 file73 file78 file82 file87 file91 file96
file100 file15 file2 file24 file29 file33 file38 file42 file47 file51 file56 file60 file65 file7 file74 file79 file83 file88 file92 file97
file11 file16 file20 file25 file3 file34 file39 file43 file48 file52 file57 file61 file66 file70 file75 file8 file84 file89 file93 file98
file12 file17 file21 file26 file30 file35 file4 file44 file49 file53 file58 file62 file67 file71 file76 file80 file85 file9 file94 file99
#修改file1...file50这50个文件的属主和属组为jin
[root@localhost a]# chown jin:jin file{1..50}
[root@localhost a]# time find ./ -user jin |wc -l
50
real 0m0.032s
user 0m0.002s
sys 0m0.003s
#使用-exec删除匹配到到文件
[root@localhost a]# time find /root/a -user jin -exec rm -rf {} \;
real 0m0.057s
user 0m0.018s
sys 0m0.032s
[root@localhost a]# ls
file100 file53 file56 file59 file62 file65 file68 file71 file74 file77 file80 file83 file86 file89 file92 file95 file98
file51 file54 file57 file60 file63 file66 file69 file72 file75 file78 file81 file84 file87 file90 file93 file96 file99
file52 file55 file58 file61 file64 file67 file70 file73 file76 file79 file82 file85 file88 file91 file94 file97
可以看到使用exec查找并删除文件属主为jin的文件一共用时0.057s,前50个文件已经被删除.
结论
在使用find查找文件并准备做批量操作时，xargs的效率比exec的效率更高效
彩蛋
使用rm命令直接删除效率更高
[root@localhost a]# touch file{1..50}
[root@localhost a]# ls
file1 file13 file18 file22 file27 file31 file36 file40 file45 file5 file54 file59 file63 file68 file72 file77 file81 file86 file90 file95
file10 file14 file19 file23 file28 file32 file37 file41 file46 file50 file55 file6 file64 file69 file73 file78 file82 file87 file91 file96
file100 file15 file2 file24 file29 file33 file38 file42 file47 file51 file56 file60 file65 file7 file74 file79 file83 file88 file92 file97
file11 file16 file20 file25 file3 file34 file39 file43 file48 file52 file57 file61 file66 file70 file75 file8 file84 file89 file93 file98
file12 file17 file21 file26 file30 file35 file4 file44 file49 file53 file58 file62 file67 file71 file76 file80 file85 file9 file94 file99
[root@localhost a]# time rm -rf file{1..50}
real 0m0.003s
user 0m0.001s
sys 0m0.002s
[root@localhost a]# ls
file100 file53 file56 file59 file62 file65 file68 file71 file74 file77 file80 file83 file86 file89 file92 file95 file98
file51 file54 file57 file60 file63 file66 file69 file72 file75 file78 file81 file84 file87 file90 file93 file96 file99
file52 file55 file58 file61 file64 file67 file70 file73 file76 file79 file82 file85 file88 file91 file94 file97