How to implement git log

Git is a very powerful version control tool. After years of development, it has now become the most familiar and used version control system for developers around the world. Among them, the log command is a very important command in Git. It can be used to view and record the historical versions of the code base, and can also be used to track and locate code problems. This article will introduce you how to implement Git log.

1. Basic usage of the log command

Before formally introducing how to implement Git's log, we need to first understand the basic usage of the log command. Specifically, the basic syntax of the log command is as follows:

$ git log [options] [commit]

Among them, options are optional, used to specify some specific parameters of the log command, such as output format, filtering conditions, etc. . commit is an optional parameter, used to specify the historical records after which version number to query. If the commit parameter is not specified, the log command will display all commit records by default, from the latest version to the oldest version.

For example, suppose we execute the following command:

$ git log

Then Git will output all submission records in the default way, including the submitter, submission time, and submission information of the code base and other information.

2. Advanced usage of log command

In addition to the basic log command syntax, we can also implement more sophisticated log query and analysis through some advanced usage. Specifically, the following are some common advanced uses of the log command:

1. Display commit records between specified versions

If we only want to view a certain time period or Commit records between one version and another version can use the <since>..<until> syntax.

For example, if we want to view the submission history from version number d6fd0b7e to version number 13afbf57, we can use the following command:

$ git log d6fd0b7e..13afbf57

2. Only display the submission record of a certain file

Sometimes, we only need to view the submission history of a specific file, rather than the submission history of the entire code base. This requirement can be achieved with the help of the --follow parameter. Specifically, the function of this parameter is to display all commit information after a file is renamed.

For example, if we want to view the submission history of the file README.md, we can execute the following command:

$ git log --follow README.md

3. Filter submission history by submitter

Sometimes, we only care about the historical version information submitted by a specific developer. For example, we need to view the submission history of a certain developer during code review. At this point, we can use the --author parameter to filter submission records. Specifically, the purpose of this parameter is to only display submission information that meets the specified author conditions.

For example, if we only want to view all historical records submitted by developer Tom, we can execute the following command:

$ git log --author=Tom

4. Change the output format of the log command

By default, the log command will output certain basic information, but if we need to output more detailed or specific information, we can do so by changing the output format. In Git, there is a --pretty parameter that can be used to change the output format.

For example, by specifying the --pretty=format: parameter, we can change the output format so that Git only displays the specified information, such as submission ID, submission time, submission description, etc. Specifically, here are some common output formats:

• %H: Displays the full hash of the commit;
• %h: Displays the short hash of the submission;
• %an: The submitter’s name;
• �: The submitter’s email Address;
• %at: submission time (UNIX timestamp format);
• %ar: submission time (relative time format, such as " 2 hours ago");
• %s: Submission instructions.

For example, if we only want to display the ID, submitter, timestamp, and submission description of each submission record, we can execute the following command:

$ git log --pretty=format:"%H - %an - %at - %s"

5. to Graphically display the submission history

If we need to display the submission history in a clearer graphical way, we can use the --graph parameter. The function of this parameter is to graphically display the version tree and branch information, allowing users to more easily understand the branch information of each submission and the branch merge status.

For example, if we want to graphically display the last 50 submission records, we can execute the following command:

$ git log --graph -n 50

3. Summary

Through the introduction of this article, We learned the basic usage and some advanced usage of Git log command. The Log command is a very important tool in Git. It can be used to view and record the historical versions of the code base, and can also be used to track and locate code problems. In actual development, it is often necessary to use the log command for version tracking and problem location, so mastering the log command is very necessary.

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