cmd: cat: add new command

Add cat command to print file content to standard out

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Roger Knecht <rknecht@pm.me>

2 files changed, 50 insertions, 0 deletions

diff --git a/doc/usage/cmd/cat.rst b/doc/usage/cmd/cat.rst
new file mode 100644
index 0000000000..5ef4731fe3
--- /dev/null
+++ b/doc/usage/cmd/cat.rst
@@ -0,0 +1,49 @@
+.. SPDX-License-Identifier: GPL-2.0+:
+
+cat command
+===============
+
+Synopsis
+--------
+
+::
+
+    cat <interface> <dev[:part]> <file>
+
+Description
+-----------
+
+The cat command prints the file content to standard out.
+
+interface
+    interface for accessing the block device (mmc, sata, scsi, usb, ....)
+
+dev
+    device number
+
+part
+    partition number, defaults to 1
+
+file
+    path to file
+
+Example
+-------
+
+Here is the output for a example text file:
+
+::
+
+    => cat mmc 0:1 hello
+    hello world
+    =>
+
+Configuration
+-------------
+
+The cat command is only available if CONFIG_CMD_CAT=y.
+
+Return value
+------------
+
+The return value $? is set to 0 (true) if the file is readable, otherwise it returns a non-zero error code.
diff --git a/doc/usage/index.rst b/doc/usage/index.rst
index d0641105ae..a05aa42485 100644
--- a/doc/usage/index.rst
+++ b/doc/usage/index.rst
@@ -31,6 +31,7 @@ Shell commands
    cmd/bootmeth
    cmd/button
    cmd/bootz
+   cmd/cat
    cmd/cbsysinfo
    cmd/cls
    cmd/conitrace