The chmod (short for change mode) command is used tomanage file system access permissions on Unix and Unix-like systems. There arethree basic file system permissions, or modes, to files anddirectories:

  1. Add_executable Depends
  2. C Make Add_executable
  3. Add_executable Cmake

CMake - the cross-platform, open-source build system. CMake is a family of tools designed to build, test and package software. CMake is used to control the software compilation process using simple platform and compiler independent configuration files. The cleanest way to achieve this would be to symlink the binary in the /usr/local/bin directory (which is included in PATH by default). You might need to create this directory if it doesn't exist yet.


Creating a Bash File. The first step is to create a new text file extension using the following. Addexecutable( ALIAS ) Creates an Alias Target, such that can be used to refer to in subsequent commands. The does not appear in the generated buildsystem as a make target.

  • read (r)
  • write (w)
  • execute (x)

Each mode can be applied to these classes:

  • user (u)
  • group (g)
  • other (o)

Add_executable Depends

The user is the account that owns the file. Thegroup that owns the file may have other accounts on the systemas members. The remaining class, other (sometimes referred toas world), means all other accounts on the system.

You can view the modes on files and directories by executing this command:

ls -l

The first field will contain 10 characters referring to the followingcharacteristics:

In the following example, file1 is readable and writable to theuser and readable to everyone on the system. file2 is readable,writable and executable by everyone. file3 is readable, writableand executable only to the user:

To change the permissions of a file, one uses the chmodcommand, with the following syntax:

chmod [references][operator][modes] filename

The references are shorthand (u,g, or o) for each class. Theoperator determines whether to add (+),remove (-) or explicitly set (=) theparticular permissions. The modes are read(r), write (w), or execute(x).

For example, to add the execute permission for the user tofile1:

chmod u+x file1

To remove the write permission for others for file2:

chmod o-w file2

You can combine multiple references and modes to set the desired access allat once. For example, to explicitly make file3 readable andexecutable to everyone:

chmod ugo=rx file3

The all (a) mode is the same as ugo, allowingthe previous command to be expressed as:


C Make Add_executable


Add_executable Cmake

chmod a=rx file3

For more information on changing permissions, run this command:

man chmod

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