Skip to main content

Documentation Index

Fetch the complete documentation index at: https://docs.syntblaze.com/llms.txt

Use this file to discover all available pages before exploring further.

The -w operator is a unary file test operator in Bash used within conditional expressions to evaluate whether a specified file exists and grants write permission to the effective user ID (EUID) of the process executing the script. Syntax 
[ -w FILE_PATH ]
[[ -w FILE_PATH ]]
test -w FILE_PATH
Evaluation Mechanics
  • True (Exit Status 0): The operand FILE_PATH resolves to an existing file, directory, or special file, AND the operating system grants write access to the current process.
  • False (Exit Status 1): The operand FILE_PATH does not exist, OR it exists but the current process lacks write access.
Technical Characteristics
  • Permission Resolution: The operator evaluates the standard POSIX permission bits (User, Group, Other) and Access Control Lists (ACLs) against the EUID and Effective Group ID (EGID) of the executing shell.
  • Directory Semantics: When applied to a directory, -w evaluates to true if the process has permission to modify the directory’s index (i.e., the ability to create, delete, or rename files within that directory).
  • Symbolic Links: The -w operator dereferences symbolic links. It evaluates the write permissions of the ultimate target file, not the link itself.
  • Filesystem State: The operator respects the mount state of the underlying filesystem at the kernel level. If a file’s permission bits allow writing, but the filesystem is mounted as read-only (ro), -w will evaluate to false.
Master Bash with Deep Grasping Methodology!Learn More