下面哪条命令可用来确保文件“my file”存在()。A.cpmyfile/dev/nullB.touch my fileC.create my fileD.mkfile my file
下面哪条命令可用来确保文件“my file”存在()。
A.cpmyfile/dev/null
B.touch my file
C.create my file
D.mkfile my file
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