Summary of LinuxShell script introduction: 3

Summary of LinuxShell script introduction: 3. split file names based on the extension. First, let's take a look at two examples: [delphi] file_jpg & quot; sample. jgp & quot; name $ {file_jpg %. *} echoFilenameis: $ name output result: Filenameissample... summary of Linux Shell script introduction: 3. split file names based on the extension. First, let's take a look at two examples: [delphi] file_jpg = "sample. jgp "name =$ {file_jpg %. *} echo File name is: $ name output result: File name is sample [delphi] extension =$ {file_jpg #*.} echo Extension is: $ extension output result: Extension is: jpg works in the first task,. expansion Get the file name in "exhibition name". We use the % operator $ {$ var %. *} meaning: 1. remove the matching string of the wildcard located on the right of % from $ var. Wildcard Matching from right to left 2. assign a value to var, so the output file name % is a non-greedy operation. It finds the shortest result of matching the wildcard from the right to the left. There is also an operator %. This operator is similar to %, but the behavior pattern is indeed greedy, which means it will match the longest string that meets the condition. In the second task, the principle is similar to %, but its running process is from left to right. The operator # Uses *. to perform greedy matching from left to right. Here is an example: in which the URL = "www.google.com" is used to batch rename a file. the following example shows how to batch rename a file. a wide range of formats are supported: first, we need to place the test image in the directory, as shown in: rename. sh is the script file that implements the function. we run the script program and get the output as follows: Let's see if the file status has actually changed. the following shows the implemented script program: [delphi] #! /Bin/bash # rename. sh count = 1; for img in *. [jJ] [pP] [gG] *. [pP] [nN] [gG] do new = image-$ count. $ {img ##*.} mv "$ img" "$ new" 2>/dev/null if [$? -Eq 0] then echo "Renaming $ img to $ new" let count ++; fi done