chmem

Set a memory block offline

$ sudo chmem [[-b|--block]] [[-d|--disable]] [block_number]

$ sudo chmem [[-b|--block]] [[-e|--enable]] [block_number]

$ sudo chmem [[-d|--disable]] 0x[start_address]-0x[end_address]

$ sudo chmem [[-e|--enable]] 0x[start_address]-0x[end_address]

$ sudo chmem [[-e|--enable]] 0x[start_address] [[-z|--zone]] [Movable]

$ chmem [[-h|--help]]

chmem is not a standard Linux command. No general synopsis or usage syntax exists for typical Linux environments. Attempts to execute it will usually result in a "command not found" error.

The command "chmem" is not a standard utility found in typical Linux distributions. Unlike commands like chmod or chown, there is no widely recognized or documented "chmem" command for changing memory characteristics or allocations. It's possible that "chmem" might refer to a highly specialized, proprietary, or custom script in a very specific environment, or it could be a typo for another command.

In standard Linux, memory management and resource allocation are handled through a variety of mechanisms: process-specific resource limits (e.g., set by ulimit), kernel parameters configurable via sysctl, direct memory allocation by applications through system calls (like mmap, brk), and tools for viewing memory statistics (like free, top, vmstat). There isn't a single command designed to "change memory" in a generic sense across the system or for arbitrary processes.

The command chmem is not a standard component of Linux operating systems. If encountered, it likely refers to a custom script, an extremely niche tool from an obscure distribution, or a command from another Unix-like system (e.g., AIX) that is not part of the Linux ecosystem. Users attempting to run chmem on a typical Linux installation will receive an error such as "bash: chmem: command not found". Memory management in Linux is granular and uses various distinct tools and kernel interfaces rather than a single 'change memory' command.

In Linux, memory is managed by the kernel's virtual memory manager (VMM). Applications request memory using system calls like mmap() or brk(). Resource limits, including memory, can be set per-user or per-process using ulimit (shell builtin) or system-wide via cgroups (control groups). Shared memory, for inter-process communication, is typically managed via POSIX shared memory (shm_open, shm_unlink) or System V IPC shared memory (shmget, shmat, shmctl), not a generic 'change memory' command.

The name "chmem" naturally suggests "change memory." While not a standard Linux command, functionality related to changing memory allocations or shared memory segments has existed under similar names or specific contexts in other Unix-like operating systems (e.g., AIX, where a chmem command exists for modifying shared memory segment sizes). In the Linux world, such functionalities are typically managed through more specialized commands, kernel interfaces, or programming constructs, rather than a single, general "chmem" utility. Its absence from standard Linux reflects the architectural differences in how memory and process resources are managed compared to some older Unix implementations.

ulimit(1), sysctl(8), free(1), top(1), vmstat(8), ipcmk(1), ipcrm(1)