Read Write on Linux

Build

1. Install Rust toolchain

   curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh

2. Build and install the executables

   make
   make install

devmem

Root privileges are required to run devmem.

Navigation

You can browse the data in /dev/mem by changing the offset value. The following table lists the key bindings that change the offset value.

Operation	Key(s)
Next Cell	l or ArrowRight
Previous Cell	h or ArrowLeft
Next Line	k or ArrowDown
Previous Line	j or ArrowUp
Next Page	n or PageDown
Previous Page	p or PageUp

In addition to above key bindings, you can also jump to specified offset. Press J, enter the offset, then press Enter. 2 types of offset are supported:

• Absolute offset. For example: E0000000.
• Relative offset, relative to current offset. For example: +FFF, -FF.

Data Type

By defaut, data is displayed in bytes. The data type can be switched with following key bindings.

Data Type	Key
Byte	B
Word	W
Double Word	D
Quad Word	Q

Data Write

In addition to browsingdata in /dev/mem, devmem also supports for writing data to /dev/mem. You can do this following below steps:

1. Change to an offset.
2. Press e.
3. Input the data to be written to the offset.
   • Specify data type by using below prefixes:

     Prefix	Data Type	Example
     B:	Byte	B:FF
     W:	Word	W:EF78
     DW:	Double Word	DW:12345678
     QW:	Quad Word	QW:1234567887654321
     DQW:	Double Quad Word	DQW:12345678876543211234567887654321

   • Data will be written to /dev/mem byte by byte if data type is not specified.
4. Press Enter.