Linux Shell intercepts strings

Linux Shell intercepts strings

There are many ways to intercept strings in the shell

${var#*/}${var##*/}${var%/*}${var%%/*}${var:start:len}${var:start}${var:0-start : Len}${var:0-start}

Here are a few examples to illustrate:

1) Get the length of the string

Grammar:

${#var}

Example code:

str="http://www.fengbohello.xin3e.com/blog/shell-truncating-string"Echo " string: [${str}] " length=${#str}echo"length: [${length}]"

Execution Result:

string : [http://www.fengbohello.xin3e.com/blog/shell-truncating-string]length: [+]

2) use # and # # to get the trailing substring 2.1) # min. intercept word from the front

Grammar:

${parameter#word}  

Example code:

str="http://www.fengbohello.xin3e.com/blog/shell-truncating-string"Echo " string: [${str}] " #分割符为 ' / ' substr=${str#*/}echo"substr: [${substr}]"

Execution Result:

string : [http:///www.fengbohello.xin3e.com/blog/shell-truncating-string]substr: [/ www.fengbohello.xin3e.com/blog/shell-truncating-string]

2.2) # # Max intercept word from front

Grammar:

${parameter# #word}

Example code:

str="http://www.fengbohello.xin3e.com/blog/shell-truncating-string"Echo " string: [${str}] " #分割符为 ' / ' substr=${str##*/}echo"substr: [${substr}]"

Execution Result:

string : [http:///www.fengbohello.xin3e.com/blog/shell-truncating-string]substr: [ shell-truncating-string]

3) Use% and percent to get the head substring 3.1)% min. intercept word from behind

Grammar:

Example code:

str="http://www.fengbohello.xin3e.com/blog/shell-truncating-string"Echo " string: [${str}] " substr=${str%/*}echo "substr: [${substr}]"

Execution Result:

string : [http://www.fengbohello.xin3e.com/blog/shell-truncating-string]substr: [http://Www.fengbohello.xin3e.com/blog]

3.2) percent of the maximum to intercept word from behind

Grammar:

${parameter%%word}

Example code:

str="http://www.fengbohello.xin3e.com/blog/shell-truncating-string"Echo " string: [${str}] " substr=${str%%/*}echo "substr: [${substr}]"

Execution Result:

string : [http://www.fengbohello.xin3e.com/blog/shell-truncating-string]substr: [http:]

4) Use ${var:} mode to get SUBSTRING 4.1) Specify the number of characters from the left and the substring of the string

Grammar:

${var:start:len}

Example code:

str="http://www.fengbohello.xin3e.com/blog/shell-truncating-string"Echo " string: [${str}] "  0 means the first character on the left begins, and7  indicates the total number of child characters. substr=${str:0:7}echo"substr: [${substr}] "

Execution Result:

string : [http:///www.fengbohello.xin3e.com/blog/shell-truncating-string]substr: [http: // ]

4.2) Start from the first few characters on the left to the end

Grammar:

${var:7}

Example code:

str="http://www.fengbohello.xin3e.com/blog/shell-truncating-string"Echo " string: [${str}] "  7  means the 8th character on the left begins substr=${str:7}echo"  SUBSTR: [${substr}]"

Execution Result:

string : [http:///www.fengbohello.xin3e.com/blog/shell-truncating-string]substr: [ www.fengbohello.xin3e.com/blog/shell-truncating-string]

4.3) Starting with the first few characters on the right and the number of characters

Grammar:

${var:0-start:len}

Example code:

str="http://www.fengbohello.xin3e.com/blog/shell-truncating-string"Echo " string: [${str}] "  0- up to the right, the 23rd character starts, and5  indicates the number of characters substr=${str:0-23 :5}echo"substr: [${substr}]"

Execution Result:

string : [http:///www.fengbohello.xin3e.com/blog/shell-truncating-string]substr: [Shell ]

4.4) Start from the first few characters on the right to the end

Grammar:

${var:0-start}

Example code:

str="http://www.fengbohello.xin3e.com/blog/shell-truncating-string"Echo " string: [${str}] "  0-6  means the 6th character starts at the right substr=${str:0-6}  echo"substr: [${substr}]"

Execution Result:

string : [http:///www.fengbohello.xin3e.com/blog/shell-truncating-string]substr: [  String]

This article was posted synchronously here:http://www.fengbohello.xin3e.com/point/p/629

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Linux Shell intercepts strings