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Many shell scripts perform actions that involve modifying filenames. They may need to rename the files and preserve the extension, or convert files from one format to another and change the extension, while preserving the name, extracting a portion of the filename, and so on.
The shell has built-in features for manipulating filenames.
The % operator will extract the name from name.extension. This example extracts sample from sample.jpg:
file_jpg="sample.jpg"
name=${file_jpg%.*}
echo File name is: $name
The output is this:
File name is: sample
The # operator will extract the extension:
Extract .jpg from the filename stored in the file_jpg variable:
extension=${file_jpg#*.}
echo Extension is...