Variable is a string with spaces, now "hdpusr400" substitution variables in a "hduser302" with:
. 1 [liusiyi @ localhost ~] $ echo $ A 2 -rw-R & lt ----- 3336 2019-07-12 17:35. 3 hduser302 hduser302 / Apps / hduser302 / Student / Properties / for xxyy / IMP_00004_XXYY_USE_PERSONALINFO.properties . 3 . 4 # replaced with the variable $ {a //} do the replacement string . 5 {a / hduser302 / hdpusr400} [liusiyi @ localhost ~] $ echo $ # variable in a first matched string will be replaced . 6 -rw-R & lt hdpusr400 hduser302 3336 2019-07-12. 3 ----- 17:35 / Apps / hduser302 / Student / Properties / for xxyy / IMP_00004_XXYY_USE_PERSONALINFO.properties . 7 [liusiyi @ localhost ~] $ echo $ {// A hduser302 / hdpusr400} # a variable all matching strings are replaced 8----- hdpusr400. 3-R & lt -rw hdpusr400 3336 2019-07-12 17:35 / Apps / hdpusr400 / Student / Properties / for xxyy / IMP_00004_XXYY_USE_PERSONALINFO.properties . 9 10 # use sed to make the replacement string . 11 [liusiyi ~ @ localhost ] $ echo $ a | Sed 'S / hduser302 / hdpusr400 /' # Sed 'S ///' to replace the first matching string 12 is -rw-R & lt hdpusr400 hduser302 3336 2019-07. 3 ----- 17:35 -12 / Apps / hduser302 / Student / Properties / for xxyy / IMP_00004_XXYY_USE_PERSONALINFO.properties 13 is [liusiyi @ localhost ~] $ echo $ A | Sed 'S / hduser302 / hdpusr400 / G' # Sed 'S /// G' It used to replace all matching strings 14----- hdpusr400. 3-R & lt -rw hdpusr400 3336 2019-07-12 17:35 / Apps / hdpusr400 / Student / Properties / for xxyy / IMP_00004_XXYY_USE_PERSONALINFO.properties 15 16 # do replacement string (in this example by using sub awk or gsub may, by default a space as a separator) . 17 [liusiyi @ localhost ~] $ echo $ a | awk '{gsub (/ hduser302 /, " hdpusr400 " , $. 3 ); Print $ 0 }' # specify replace the first 18 is -rw-R & lt ----- 3336 2019-07-12 17:35. 3 hdpusr400 hduser302 / Apps / hduser302 / Student / Properties / for xxyy / IMP_00004_XXYY_USE_PERSONALINFO.properties . 19 [liusiyi @ localhost ~] $ echo $ A | awk ' gsub {(/ hduser302 /, "hdpusr400 " ); Print $ 0 } ' # replace all 20 is -rw-R & lt hdpusr400 hdpusr400. 3 ----- 3336 2019-07-12 17:35 /apps/hdpusr400/student/properties/xxyy/IMP_00004_XXYY_USE_PERSONALINFO.properties
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