Linux-shopt-s Extglob

The Bash Shell has a extglob option that allows the shell to identify 5 additional pattern matching operators, which makes it easier to match files.

The Open method is simple, using the shopt command: Shopt-s extglob
Close, use the shopt command: Shopt-u extglob

After opening, the following 5 pattern matching operators will be identified:

? (pattern-list)-the given pattern matches 0 or 1 times, * (Pattern-list)-the given pattern matches 0 times above including 0 times, + (pattern-list)-The given pattern matches 1 times above including 1 times; @ (pattern-list)- The given pattern only matches 1 times;! (pattern-list)-does not match the given pattern in parentheses.


Example


Delete files with file names that do not end in JPG:


Rm-rf! (*jpg)

Delete files with file names ending in jpg or PNG:

RM-RF *@ (jpg|png)


shopt Command

Built-in command shopt (Shell option) turns on, off, and lists some of the bash features that control the behavior of the shell. For example, the following command will cause bash to include those with a period (.) When extending the fuzzy file reference. The initial file name,-S, indicates the setting:

$ shopt-s Dotglob

This feature can be turned off by the following command (default), and-U represents the Cancel setting:

$ shopt-u Dotglob

If you only use the name of the attribute as the shopt unique parameter, the shell shows how the attribute is set:

$ shopt Dotglob

Dotglob off

When the command shopt does not have any options or parameters, the attributes and their states that are controlled by Shopt are listed. When the command shopt-s without parameters, those attributes that are controlled by shopt and set to on are listed. The command shopt–u will list the bash features that were canceled or closed. Table 8-13 lists the bash features.

Setting Set±o features using shopt

Tip You can use shopt to set or cancel features that are controlled by Set±o. Use the regular shopt–s or-u syntax and include the-o option. For example, the following command will turn on the Noclobber feature:

$ shopt–o–s Noclobber

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Linux-shopt-s Extglob