版权
变量a是一个带空格的字符串,现在用"hdpusr400"替换变量a中的"hduser302":
[liusiyi@localhost ~]$ echo $a -rw-r----- 3 hduser302 hduser302 3336 2019-07-12 17:35 /apps/hduser302/student/properties/xxyy/IMP_00004_XXYY_USE_PERSONALINFO.properties #用变量替换${a//}做字符串替换 [liusiyi@localhost ~]$ echo ${a/hduser302/hdpusr400} #变量a中的第一个匹配的字符串会被替换 -rw-r----- 3 hdpusr400 hduser302 3336 2019-07-12 17:35 /apps/hduser302/student/properties/xxyy/IMP_00004_XXYY_USE_PERSONALINFO.properties [liusiyi@localhost ~]$ echo ${a//hduser302/hdpusr400} #变量a中所有匹配的字符串都会被替换 -rw-r----- 3 hdpusr400 hdpusr400 3336 2019-07-12 17:35 /apps/hdpusr400/student/properties/xxyy/IMP_00004_XXYY_USE_PERSONALINFO.properties #用sed做字符串替换 [liusiyi@localhost ~]$ echo $a | sed 's/hduser302/hdpusr400/' #sed 's///' 用来替换第一个匹配的字符串 -rw-r----- 3 hdpusr400 hduser302 3336 2019-07-12 17:35 /apps/hduser302/student/properties/xxyy/IMP_00004_XXYY_USE_PERSONALINFO.properties [liusiyi@localhost ~]$ echo $a | sed 's/hduser302/hdpusr400/g' #sed 's///g'用来替换所有匹配的字符串 -rw-r--