Multiple methods for string interception in shell scripts

1. #号截取, remove the left character and leave the right character.     

Code: Echo ${var#*//}

where Var is the variable name, #是运算符, *//indicates that the first//and all characters on the left are deleted from the left.    

Example:

650) this.width=650; "src=" Http://s2.51cto.com/wyfs02/M02/83/87/wKiom1d1FsDzeXPlAAAkuhf70v0980.png "title=" Str1.1.png "alt=" Wkiom1d1fsdzexplaaakuhf70v0980.png "/>

Results:

650) this.width=650; "src=" Http://s4.51cto.com/wyfs02/M00/83/85/wKioL1d1FtKCNfcvAAAbGnoHuHw096.png "title=" Str1.2.png "alt=" Wkiol1d1ftkcnfcvaaabgnohuhw096.png "/>

2.# #截取, remove left character, leave right character

Code: Echo ${var##*/}

Where ##*/indicates that the last (rightmost) one/number and all characters to the left are deleted from the left.

Example:

650) this.width=650; "src=" Http://s4.51cto.com/wyfs02/M01/83/85/wKioL1d1F0-j5jSQAAAkWjWuxEE672.png "title=" Str2.1.png "alt=" Wkiol1d1f0-j5jsqaaakwjwuxee672.png "/>

Results:

650) this.width=650; "src=" Http://s1.51cto.com/wyfs02/M00/83/85/wKioL1d1FxvTSeWfAAATSoV__qA698.png "title=" Str2.2.png "alt=" Wkiol1d1fxvtsewfaaatsov__qa698.png "/>

3.%, delete the right character, leave the left character

Code: Echo ${var%/*}

where%/* means to start from the right, delete the first/second and right character

Example:

650) this.width=650; "src=" Http://s5.51cto.com/wyfs02/M01/83/87/wKiom1d1F3OyGvwQAAAfiw07HIw095.png "title=" Str3.1.png "alt=" Wkiom1d1f3oygvwqaaafiw07hiw095.png "/>

Results:

650) this.width=650; "src=" Http://s2.51cto.com/wyfs02/M02/83/85/wKioL1d1F4_B0FdrAAAR14_VFpQ326.png "title=" Str3.2.png "alt=" Wkiol1d1f4_b0fdraaar14_vfpq326.png "/>

4.%%, delete the right character, leave the left character

Code: Echo ${%%/*}

Where%%/* means to delete the last (leftmost) one/and right character from the right

Example:

650) this.width=650; "src=" Http://s2.51cto.com/wyfs02/M02/83/87/wKiom1d1F7zgIq6aAAAi3YD4qSs128.png "title=" Str4.1.png "alt=" Wkiom1d1f7zgiq6aaaai3yd4qss128.png "/>

Results:

650) this.width=650; "src=" Http://s5.51cto.com/wyfs02/M01/83/85/wKioL1d1F9SzSUMkAAASARyFREk192.png "title=" Str4.2.png "alt=" Wkiol1d1f9szsumkaaasaryfrek192.png "/>

5. Start with the first few characters on the left and the number of characters

Code: Echo ${var:0:5}

Where 0 means the first character on the left begins, and 5 indicates the total number of characters

Example:

650) this.width=650; "src=" Http://s4.51cto.com/wyfs02/M00/83/85/wKioL1d1F_LxOI4CAAAfQX4E6Kw673.png "title=" Str5.1.png "alt=" Wkiol1d1f_lxoi4caaafqx4e6kw673.png "/>

Results:

650) this.width=650; "src=" Http://s2.51cto.com/wyfs02/M00/83/87/wKiom1d1GAvw-9DzAAAR3ahksnc030.png "title=" Str5.2.png "alt=" Wkiom1d1gavw-9dzaaar3ahksnc030.png "/>

6. Starting from the first few characters on the left, until the end

Code: Echo ${var:7}

7 of these means starting with the 8th character on the left, until the end

Example:

650) this.width=650; "src=" Http://s3.51cto.com/wyfs02/M01/83/87/wKiom1d1GE_Ac3DBAAAegVxfewY289.png "title=" Str6.1.png "alt=" Wkiom1d1ge_ac3dbaaaegvxfewy289.png "/>

Results:

650) this.width=650; "src=" Http://s1.51cto.com/wyfs02/M02/83/85/wKioL1d1GGXg_ZeOAAAR4UFJcYQ920.png "title=" Str6.2.png "alt=" Wkiol1d1ggxg_zeoaaar4ufjcyq920.png "/>

7. Start with the first few characters on the right and the number of characters

Code: Echo ${var:0-7:3}

Where 0-7 means starting at the seventh character from the right, and 3 representing the number of characters

Example:

650) this.width=650; "src=" Http://s3.51cto.com/wyfs02/M02/83/85/wKioL1d1GISDMwMGAAAgxRgV-TA690.png "title=" Str7.1.png "alt=" Wkiol1d1gisdmwmgaaagxrgv-ta690.png "/>

Results:

650) this.width=650; "src=" Http://s2.51cto.com/wyfs02/M02/83/87/wKiom1d1GJrDTl-jAAARGj_2i5Y592.png "title=" Str7.2.png "alt=" Wkiom1d1gjrdtl-jaaargj_2i5y592.png "/>

8. Start from the first few characters on the right until the end

Code: Echo ${var:0-7}

Starts at the seventh character on the right, until the end

Example:

650) this.width=650; "src=" Http://s4.51cto.com/wyfs02/M01/83/85/wKioL1d1GNCieDBkAAAkJ6UW224077.png "title=" Str8.1.png "alt=" Wkiol1d1gnciedbkaaakj6uw224077.png "/>

Results:

650) this.width=650; "src=" Http://s1.51cto.com/wyfs02/M01/83/87/wKiom1d1GOTzdq-DAAAVINH68Ps927.png "title=" Str8.2.png "alt=" Wkiom1d1gotzdq-daaavinh68ps927.png "/>

The 9.cut command mainly accepts three positioning methods:

(1) Bytes, with option-B

(2) Character, with option-C

(3) Domain, with option-f

Example:

650) this.width=650; "src=" Http://s3.51cto.com/wyfs02/M01/83/87/wKiom1d1HLSgJ4OIAABNiwg3THI043.png "title=" Cut1.png "alt=" Wkiom1d1hlsgj4oiaabniwg3thi043.png "/>

So it seems that the-B and-C options are no different, it is not, because the WHO output are single-byte characters, so with-B and c no difference, if changed to Chinese, then only C can be used, and-B output is garbled.

We mentioned that-B and-C can only extract information in a fixed-format document, and for non-fixed format information is useless, then the "domain" is used.

Example:

650) this.width=650; "src=" Http://s4.51cto.com/wyfs02/M02/83/87/wKiom1d1HzDBZwTMAACNN0iFyA0689.png "title=" Cut2.png "alt=" Wkiom1d1hzdbzwtmaacnn0ifya0689.png "/>

This article is from the "Zwy" blog, make sure to keep this source http://10548195.blog.51cto.com/10538195/1794726

Multiple methods for string interception in shell scripts