nfscat - read a file over NFS and print to stdout
nfscat [-hTv] [-b blocksize] [-c count] [-H hertz] [-S source]
nfscat sends NFS version 3 READ RPC requests to an NFS server and prints the file contents in the responses to stdout. It starts at the beginning of the file and will read it until the end unless a number of requests is specified with the -c option.
The filehandles to be read are passed on stdin as a series of JSON objects (one per line) with the keys "host", "ip", "path", and "filehandle", where the value of the "filehandle" key is the hex representation of the file's NFS filehandle.
If the NFS server requires "secure" ports (<1024), nfscat will have to be run as root.
-bSet the blocksize for requests in bytes. Default is 8192.
-cCount of requests to send for each file before exiting. Instead of printing the file contents to stdout, print a summary line for each request with the response time.
-hDisplay a help message and exit.
-H hertzThe polling frequency in Hertz. This is the number of requests sent to each target per second. Default = 1.
-S sourceUse the specified source IP address for request packets.
-TUse TCP to connect to server. Default = UDP.
-vDisplay debug output on stderr.
Here is a pipeline of commands which demonstrates using nfsmount to obtain the root filehandle, then using nfsls to find the filehandle for /etc/hosts and finally nfscat to print the contents:
sudo sh -c "nfsmount dumpy:/ | nfsls | grep etc | nfsls | grep hosts | nfscat"
nfscat will return 0 if all requests to all targets received successful responses. Nonzero exit codes indicate a failure. 1 is an RPC error, 2 is a name resolution failure, 3 is an initialisation failure (typically bad arguments).
Matt Provost, mprovost@termcap.net
Copyright 2017 Matt Provost
RPC files Copyright Sun Microsystems
NFSv4 files Copyright IETF
nfsmount(8), nfsls(8)