HowTo: Linux Limit A Specific User’s Shell Account Network Bandwidth Using Bash Shell and Trickle

I am using a bash shell under Ubuntu Linux operating system. Sometime I need to restrict my own Internet bandwidth for all my shell applications such as ftp, sftp, wget, curl and friends. How do I limit the network speed under bash without setting up a complicated firewall and tc rules as described here?

You need to use a portable lightweight userspace bandwidth shaper called trickle. It can run in in collaborative mode or in stand alone mode. trickle works by taking advantage of the unix loader preloading. Essentially it provides, to the application, a new version of the functionality that is required to send and receive data through sockets. It then limits traffic based on delaying the sending and receiving of data over a socket. trickle runs entirely in userspace and does not require root access.


Type the following apt-get command under Debian / Ubuntu Linux to install trickle software:
$ sudo apt-get install trickle
Sample outputs:

Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following NEW packages will be installed:
0 upgraded, 1 newly installed, 0 to remove and 20 not upgraded.
Need to get 43.0 kB of archives.
After this operation, 180 kB of additional disk space will be used.
Get:1 squeeze/main trickle amd64 1.07-9 [43.0 kB]
Fetched 43.0 kB in 1s (30.6 kB/s)                     
Selecting previously deselected package trickle.
(Reading database ... 280975 files and directories currently installed.)
Unpacking trickle (from .../trickle_1.07-9_amd64.deb) ...
Processing triggers for man-db ...
Setting up trickle (1.07-9) ...

Install trickle under CentOS / RHEL / Fedora Linux

First, turn on EPEL repo and type the following yum command to install trickle software:
# yum install trickle
Sample outputs:

Loaded plugins: auto-update-debuginfo, protectbase, rhnplugin
0 packages excluded due to repository protections
Setting up Install Process
Resolving Dependencies
--> Running transaction check
---> Package trickle.x86_64 0:1.07-9.el6 will be installed
--> Finished Dependency Resolution

Dependencies Resolved

 Package      Arch        Version            Repository
 trickle      x86_64      1.07-9.el6         epel       41 k

Transaction Summary
Install       1 Package(s)

Total download size: 41 k
Installed size: 89 k
Is this ok [y/N]: y
Downloading Packages:
trickle-1.07-9.el6.x86_64.rpm         |  41 kB     00:00     
Running rpm_check_debug
Running Transaction Test
Transaction Test Succeeded
Running Transaction
  Installing : trickle-1.07-9.el6.x86_64                 1/1 
  Verifying  : trickle-1.07-9.el6.x86_64                 1/1 

  trickle.x86_64 0:1.07-9.el6                                


How do I use trickle?

The syntax is:

trickle -u uploadLimit program
trickle -d downloadLimit program
trickle -u {UPLOAD_LIMIT} -d {DOWNLOAD_LIMIT} program-binary


Start ftp client limiting its upload capacity to 100 KB/s:
trickle -u 100 ftp
Start ftp client limiting its download capacity at 50 KB/s:
trickle -d 50 ftp
You can combine both options:
trickle -u 100 -d 50 ftp
You can pass other args to the ftp command:
trickle -u 100 -d 50 ftp
trickle -u 100 -d 50 ftp 8021

Use the wget command to download an iso file from ftp server:
$ wget
Sample outputs:

--2012-12-04 16:00:16--
Connecting to||:80... connected.
HTTP request sent, awaiting response... 206 Partial Content
Length: 237457408 (226M), 230422880 (220M) remaining [text/plain]
Saving to: `install52.iso'

 7% [>                   ] 1,86,94,640 2.94M/s  eta 79s 

Now, use trickle to download iso file but limit capacity at 50 KB/s:
trickle -d 50 wget
Sample outputs:

trickle: Could not reach trickled, working independently: No such file or directory
--2012-12-04 16:00:32--
Connecting to||:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 237457408 (226M) [text/plain]
Saving to: `install52.iso.2'

 0% [                    ] 2,45,760    49.9K/s  eta 77m 22s

Limit bandwidth in a single shell for all commands

Launch bash or ksh shell limiting its upload capacity to 250 KB/s, and download capacity at 500 KB/s:
trickle -d 500 -u 250 bash
trickle -d 500 -u 250 ksh
Now, for all programs launched inside currently running bash or ksh shell will follow bandwidth shaper rules:
sftp file.mp4 [email protected]:~/Downloads/

Other options

From the man page:

	-h           Help (this)
	-v           Increase verbosity level
	-V           Print trickle version
	-s           Run trickle in standalone mode independent of trickled
	-d     Set maximum cumulative download rate to  KB/s
	-u     Set maximum cumulative upload rate to  KB/s
	-w   Set window length to  KB 
	-t  Set default smoothing time to  s
	-l   Set default smoothing length to  KB
	-n     Use trickled socket name 
	-L       Set latency to  milliseconds

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Posted by: SXI ADMIN

The author is the creator of SXI LLC and a seasoned sysadmin, DevOps engineer, and a trainer for the Linux operating system/Unix shell scripting. Get the latest tutorials on SysAdmin, Linux/Unix and open source topics via RSS/XML feed or weekly email newsletter.