What is the meaning of chmod?
On Linux and other Unix-like operating systems, there is a set of rules for each file which defines who can access that file, and how they can access it. These rules are called file permissions or file modes. The command name chmod stands for "change mode", and it is used to define the way a file can be accessed.
where nnn is the 3-digit number representing the permissions, and filename is the file you want to change. For example: chmod 755 formmail.cgi. will assign read, write and execute permission to the owner, and just read and execute permission to everyone else, on the script called formmail.cgi .
- In short, “chmod 777” means making the file readable, writable and executable by everyone. chmod 775 /path/to/file. Hopefully, this article can help you understand better about the file permissions in Unix system and the origin of the magical number “777”.
- Who “owns” Linux? By virtue of its open source licensing, Linux is freely available to anyone. However, the trademark on the name “Linux” rests with its creator, Linus Torvalds. The source code for Linux is under copyright by its many individual authors, and licensed under the GPLv2 license.
- The kill command is used on Linux and other Unix-like operating systems to terminate processes without having to log out or reboot (i.e., restart) the computer. Thus, it is particularly important to the stability of such systems.
When you perform the chmod 755 filename command you allow everyone to read and execute the file, and the file owner is allowed to write to the file as well. You may need this for Perl and other scripts that should to be run via a webserver.
- Electronic intelligence (ELINT) is intelligence gathered by the use of electronic sensors. In ELINT, intelligence gathered is generally those other than personal communications. The purpose is often to ascertain the capabilities of a target, such as the location of radar.
- Measurement and signature intelligence (MASINT) is a technical branch of intelligence gathering, which serves to detect, track, identify or describe the signatures (distinctive characteristics) of fixed or dynamic target sources.
- A geographic information system (GIS) is a system designed to capture, store, manipulate, analyze, manage, and present all types of geographical data. The key word to this technology is Geography – this means that some portion of the data is spatial.
You'd use chmod like this to set no special permissions: chmod 0750 myscript.sh . Sticky bit A value of 1. This bit is commonly set to directories and means that you may only remove file in such a directory that are owned by you. If this permission is given, the program is executed as the Owner of the file.
- In the terminal, the command to use to change file permission is “ chmod “. In short, “chmod 777” means making the file readable, writable and executable by everyone. chmod 775 /path/to/file.
- In Unix-like operating systems, chmod is the command and system call which may change the access permissions to file system objects (files and directories). It may also alter special mode flags. The request is filtered by the umask. The name is an abbreviation of change mode.
- Typically a .sh file is a shell script which you can execute in a terminal. Specifically, the script you mentioned is a bash script, which you can see if you open the file and look in the first line of the file, which is called the shebang or magic line.
Updated: 2nd October 2019