tsshbatch - Run Commands On Batches Of Machines
tsshbatch is a powerful tool for automating activities
on many servers at a time. This also gives you to power
to make many mistakes at a time! This is especially
true if you have
sudo privilege promotion
capabilities on the systems in your care. So be careful
We therefore STRONGLY recommend you do the following
things to mitigate this risk:
- Read This Fine Manual from beginning to end.
- Practice using
tsshbatch on test machines or
VMs that can easily be recovered or reimaged if you
- Make heavy use of test mode (which is the default)
to see what the program would do if it actually
ran in execution mode.
tsshbatch.py [-EKLNSTWaehkqrstvxy -G 'file dest' -P 'file dest' -f cmdfile -l logfile -n name -p pw ] -H 'host ..' -i 'hostfile ...' [command arg ... ]
tsshbatch is a tool to enable you to issue a command to many
hosts without having to log into each one separately. When writing
scripts, this overcomes the
ssh limitation of not being able to
specify the password on the command line.
You can also use
from- and to many hosts at once.
tsshbatch also understands basic
sudo syntax and can be used
to access a host,
sudo a command, and then exit.
tsshbatch thus allows you to write complex, hands-off scripts that
issue commands to many hosts without the tedium of manual login and
sudo promotion. System administrators, especially, will find this
helpful when working in large server farms.
tsshbatch supports a variety of options which can be specified
on either the command line or in the
||Print start, stop, and elapsed execution time
statistics. This does not include any time
spent for interactive prompting and response,
but reflects actual program runtime. (Default: Off)
||Specify the location of the ssh configuration
tsshbatch writes it's own errors
stderr. It also writes the
output from each host it contacts to the local
stderr (unless the
-e option has
-E option redirects any such
output intended for
instead. This avoids the need to do things like
2>&1 | ...` on the command line when you want to
pipe all ``tsshbatch output to another program.
This will examine every file on the host- or
command paths, looking for matching strings within
these files. Matches will report the file name,
the location within the file, and the line
containing any of the specified strings.
This is a simple, case-insensitive string literal
match and does not support regular expressions.
This is handy when you're looking for a host name
or command string, say like,
sudo and you don't
want to have to manually go through all your
||Force prompting for passwords. This is used
to override a prior
GET file on host and write local dest directory.
spec is a quoted pair of strings. The first
specifies the path of the source file (on the
remote machine) to copy. The second, specifies
the destination directory (on the local
tsshbatch.py -G "/foo/bar/baz /tmp" -i hostlist
/foo/bar/baz from every machine in
host file to the local
Since all the files have the same name, they would
overwrite each other if copied into the same
tsshbatch prepends the string
hostname- to the name of each file it saves
List of hosts on which to run the command. This should
be enclosed in quotes so that the list of hosts
is handed to the -H option as a single argument:
-H 'host1 host2 host3'
This option may appear on the command line multiple
times. The hosts will be processed in the order
in which they appeared on the command line.
||List names of all (if any) host- and command files
found on their respective search paths. These are
listed in the order they are found on those paths.
||Force interactive username dialog. This cancels
any previous request for key exchange authentication.
PUT file from local machine to remote machine destination
spec is a quoted pair of strings.
The first specifies the path of the source file (on
the local machine) to copy. The second, specifies
the destination directory (on the remote machine):
tsshbatch.py -P "/foo/bar/baz /tmp" -i hostlist
/foo/bar/baz on the local
/tmp/ on every host in
||Force prompting for
||Set timeout for ssh connection attempts. (Default: 15 seconds)
||Similar to the
-F command but with the inverse logic.
Reports the names of all host- and command files that
do not contain any of the specified strings.
Print out a single line list of the inventory that would
be processed and exit. (Test mode only - Ignored in
This allows you to embed
tsshbatch in external
shell scripts like this:
for server in $(tsshbatch.py -i devserverlist -i uatserverlist -W)
Why? Because tsshbatch has lots of powerful ways
to maintain inventories of hosts and combine them
through includes and multiple command line
-W option makes it convenient for
external programs to make use of those inventory
||Don't abort program after failed file transfers.
Continue to next transfer attempt. (Default: Abort)
||Don't abort program after failed
sudo command. Normally, any
sudo failure causes immediate program termination. This
tsshbatch to continue processing on the
next host even if such a failure occurs. This allows
processing to continue for those hosts where
work correctly. This is helpful in large environments where
sudo is either improperly configured on some hosts or
has a different password. This can also be used to discover
sudo does- and does not work correctly.
||Don't report remote host
||Read commands from a file. This file can be commented
freely with the
# character. Leading- and
trailing whitespace on a line are ignored.
||Print help information.
Specify which files to read to get a list of desired
hosts to target. This option may be repeated on the
command line and may also be followed with a quoted
list of such files. The following are equivalent:
tsshbatch.py -i devservers -i uatservers ...
tsstbatch.py -i "devservers uatservers" ...
-i options can be freely
combined and repated on the command line to create
custom host lists made up of both known inventory
and specific, individual hosts.
||Use ssh keys instead of name/password credentials.
||Log diagnostic output to
||Login name to use.
||Password to use when logging in and/or doing
||Quiet mode - produce less noisy output. Turns off
||Suppress reporting of start/stop statistics. This
allows you to make statistics reporting the
default, say via the
variable, but override it when you need to.
||Silence all program noise - only return command output.
Applies only to command operations. File transfer
and error reporting, generally, are unaffected.
||Test mode: Only show what would be done but don't
actually do it. This also prints diagnostic
information about any variable definitions, the list
of hosts, any
PUT requests, and final
command strings after all variable substitutions have
been applied. This is the default program behavior.
||Print detailed program version information and exit.
||Override any previous
-t specifications and
actually execute the commands. This is useful
if you want to put
-t in the
environment variable so that the default is
always run the program in test mode. Then, when
you're ready to actually run commands, you can
override it with
-x on the command line.
||Turn on 'noisy' reporting for additional detail on
every line, instead of just at the top of the
stderr reporting. This is
helpful when you are filtering the output through
grep that only returns matching
lines and thus no context information. Turns off
The last entry on the command line is optional and defines a command
tsshbatch will attempt to execute it on every host you've
specified either via
-H or a host file:
tsshbatch.py -Hmyhost ls -al /etc
This will do a
ls -al /etc on
Be careful when using metacharacters like
&&, <<, >>, <, > and so
on in your commands. You have to escape and quote them properly or
your local shell will interfere with them being properly conveyed to
the remote machine.
tsshbatch does all the
GETs, then all the
attempting to do any command processing. If no
commands have been specified,
tsshbatch will exit silently, since
"nothing to do" really isn't an error.
tsshbatch respects the
$TSSHBATCH environment variable. You
may set this variable with any options above you commonly use to avoid
having to key them in each time you run the program. For example:
export TSSHBATCH="-n jluser -p l00n3y"
This would cause all subsequent invocations of
attempt to use the login name/password credentials of
tsshbatch also supports searching for files over specified
paths with the
variables. Their use is described later in this document.
SSH CONFIGURATION FILE PROCESSING
tsshbatch has limited support for ssh configuration files. Only the
IdentityFile directives are currently supported.
tsshbatch will look in
~/.ssh/config for this
configuration file. However, the location of the file can be
overriden with the
MANAGING INVENTORY: HOST FILES
Although you can specify a list of target hosts with one or more
"host host host" command line options, this gets cumbersome when you
have to manage a large inventory of machines. This is what "host files"
are intended to do.
Host files are files that name a host, one per line. They may
contain comments, include other host files, and make reference to
previously defined variables. Here's an example, let's call it
# Example staging host list
.define __EXTERNAL__ = splat.com
Say you'd like to get the uptime for each of these servers:
tsshbatch.py -x -i stage-servers uptime
You can have more than one of these on a command line so this is
tsshbatch.py -x -i dev-servers -i stage-servers -i prod-servers uptime
But ... that's kind of clumsy. Instead let's create a new host file
all-servers like this:
# Master host list
Now our command looks like this:
tsshbatch.py -x -i all-servers uptime
You can put as many
-i arguments as you wish on the command line.
The contents of these files will be run in the order they appear from
left-to-right on the command line.
You can organize your host files in any hierarchy you like by making
use of search paths, as described later in this document.
The use of host files, the
-H command line option,
and variable substitution, give
tsshbatch a very powerful way to
manage complex host inventories. There may be times when you'd like
to select a subset of that inventory but run some other program with
those host names. This is most commonly the case when you'd like to
ssh into each host for some reason.
That's what the
-W command line option is for.
the inventory you've specified, spits it out as single line of text and exits,
thereby enabling things like this:
for server in $(tsshbatch.py -i dev-servers -i dr-servers -W)
This allows you to do all your intentory management via
constructs, but make use of it with any other program of your
MANAGING JOBS: COMMAND FILES
tsshbatch accepts command to be run on each host on its
own command line, this gets cumbersome for multi-step activities. The
-f option allows you to specify one or more "command files" that
list the things you want done, in order.
Command files may include other command files, make use of variables,
and even specify sudo commands. For example:
# This is a comment
.include master_commands # optional, can be repeated
command1 # a command to run on each host
sudo foo # run foo with sudo promotion on each host
Notice that this is not the same thing as a shell script. There are
no conditionals or other programming features. The contents of a
command file are more-or-less a "to do" list for each host. If your
job requires the complexity of a "real" language, write script in
the language of your choice, and then make reference to that script
in a command file.
If you've specified a command file containing the commands you want run
-f option, these commands will run before the command
you've defined on the command line. That one is always the last
command run on each host.
Command files may freely make use of comments and variable definitions
as described below. They also have a special directive available,
.notify. This directive tells
tsshbatch to print descriptive
stdout as the commands in the file are executed on a
remote host. This is helpful when running long, complex jobs:
# Example cmdfile
.notify starting JOB_NAME processing
.notify starting phase 2 of __JOB_NAME__
Notifications are entirely optional and do not run on the remote
host. Think of them as runtime comments emitted by
help you know what's going on. Notifications are supressed if you
select silent operation (
You can also specify file transfers within a command file. See the
section below on file transfers for all the details.
You can put as many
-f arguments as you wish on the command line.
The contents of these files will be run in the order they appeare from
left-to-right on the command line.
You can organize your command files in any hierarchy you like by making
use of search paths, as described later in this document.
SEARCHING YOUR HOST AND COMMAND FILES
Over time, you will probably build up a large set of host files for
describing your inventory and host files for standard jobs you
run often. It's convenient to search through them quickly when
you're looking for something specific.
-L command line option just lists every host file and command
tsshbatch knows about on all defined search paths. This is
handly if you want to examine your hierarchy of files.
-F string string ... command line option looks through all
your host and command files and returns the names of those that
contain any of the strings you've listed. The match is case
insensitive and literal - no regular expressions are supported.
-V string string ... command line option is the inverse
-F. It returns a list of host and command files that do
not contain the strings you specify. Again, the match is
a simple, literal case-insensitive test.
FEATURES AND USE CASES
The sections below describe the various features of
more detail as well as common use scenarios.
Different Ways To Specify Targeted Hostnames
There are two ways to specify the list of hosts on which you want
to run the specified command:
On the command line via the
tsshbatch.py -H 'hostA hostB' uname -a
This would run the command
uname -a on the
Notice that the list of hosts must be separated by spaces but
passed as a single argument. Hence we enclose them in single
Via a host list file:
tsshbatch.py myhosts df -Ph
tsshbatch expects the file
myhosts to contain a list
of hosts, one per line, on which to run the command
df -Ph. As
an example, if you want to target the hosts
myhosts would look like this:
This method is handy when there are standard "sets" of hosts on
which you regularly work. For instance, you may wish to keep a
host file list for each of your production hosts, each of your
test hosts, each of your AIX hosts, and so on.
You may use the
# comment character freely throughout a host
list file to add comments or temporarily comment out a particular
You can even use the comment character to temporarily comment out
one or most hosts in the list given to the
-H command line
argument. For example:
tsshbatch.py -H "foo #bar baz" ls
This would run the
ls command on hosts
bar. This is handy if you want to use your shell's
command line recall to save typing but only want to repeat the
command for some of the hosts your originally Specified.
Authentication Using Name And Password
The simplest way to use
tsshbatch is to just name the hosts
can command you want to run:
tsshbatch.py linux-prod-hosts uptime
tsshbatch uses your login name found in the
environment variable when logging into other systems. In this
example, you'll be prompted only for your password which
will then use to log into each of the machines named in
linux-prod-hosts. (Notice that his assumes your name and
password are the same on each host!)
Typing in your login credentials all the time can get tedious after
tsshbatch provides a means of providing them on the
tsshbatch.py -n joe.luser -p my_weak_pw linux-prod-hosts uptime
This allows you to use
tsshbatch inside scripts for hands-free
If your login name is the same on all hosts, you can simplify this
further by defining it in the environment variable:
export TSSHBATCH="-n joe.luser"
Any subsequent invocation of
tsshbatch will only require a
password to run.
HOWEVER, there is a huge downside to this - your plain text password
is exposed in your scripts, on the command line, and possibly your
command history. This is a pretty big security hole, especially if
you're an administrator with extensive privileges. (This is why the
ssh program does not support such an option.) For this reason, it
is strongly recommended that you use the
-p option sparingly, or
not at all. A better way is to push ssh keys to every machine and use
key exchange authentication as described below.
However, there are times when you do have use an explicit password,
such as when doing
sudo invocations. It would be really nice to
-p and avoid having to constantly type in the password. There
are two strategies for doing this more securely than just entering it
in plain text on the command line:
Temporarily store it in the environment variable:
export TSSHBATCH="-n joe.luser -p my_weak_pw"
Do this interactively after you log in, not from a script
(otherwise you'd just be storing the plain text password in a
different script). The environment variable will persist as long
as you're logged in and disappear when you log out.
If you use this just make sure to observe three security
- Clear your screen immediately after doing this so no one
walking by can see the password you just entered.
- Configure your shell history system to ignore commands
export TSSHBATCH. That way your plain
text password will never appear in the shell command history.
- Make sure you don't leave a logged in session unlocked so
that other users could walk up and see your password by
displaying the environment.
This approach is best when you want your login credentials
available for the duration of an entire login session.
Store your password in an encrypted file and decrypt it inline.
First, you have to store your password in an encrypted format.
There are several ways to do this, but
gpg is commonly used:
echo "my_weak_pw" | gpg -c >mysecretpw
Provide a decrypt passphrase, and you're done.
Now, you can use this by decrypting it inline as needed:
# A demo scripted use of tsshbatch with CLI password passing
MYPW=`cat mysecretpw | gpg` # User will be prompted for unlock passphrase
tsshbatch.py -n joe.luser -p $MYPW -i hostlist1 command1 arg
tsshbatch.py -n joe.luser -p $MYPW -i hostlist2 command2 arg
tsshbatch.py -n joe.luser -p $MYPW -i hostlist3 command3 arg
This approach is best when you want your login credentials
available for the duration of the execution of a script. It
does require the user to type in a passphrase to unlock the
encrypted password file, but your plain text password never
appears in the wild.
Authentication Using Key Exchange
For most applications of
tsshbatch, it is much simpler to use
key-based authentication. For this to work, you must first have
pushed ssh keys to all your hosts. You then instruct
use key-based authentication rather than name and password. Not only
does this eliminate the need to constantly provide name and password,
it also eliminates passing a plain text password on the command line
and is thus far more secure. This also overcomes the problem of
having different name/password credentials on different hosts.
tsshbatch will prompt for name and password if they
are not provided on the command line. To force key- authentication,
tsshbatch.py -k AIX-prod-hosts ls -al
This is so common that you may want to set it in your
environment variable so that keys are used by default. If you do
this, there may still be times when you want for force prompting for
passwords rather than using keys. You can do this with the
option which effectively overrides any prior
tsshbatch is smart enough to handle commands that begin with the
sudo command. It knows that such commands require a password no
matter how you initially authenticate to get into the system. If you
provide a password - either via interactive entry or the
option - by default,
tsshbatch will use that same password for
If you provide no password - you're using
-k and have not provided
a password via
tsshbatch will prompt you for the password
sudo should use.
You can force
tsshbatch to ask you for a
sudo password with
-S option. This allows you to have one password for initial
login, and a different one for
Any time you a prompted for a
sudo password and a login password
has been provided (interactive or
-p), you can accept this as the
sudo password by just hitting
tsshbatch makes a reasonable effort to scan your command
line and/or command file contents to spot explicit
invocations of the form
sudo .... It will ignore these
if they are inside single- or double quoted strings, on the
assumption that you're quoting the literal string
... for some other purpose.
However, this is not perfect because it is not a full
reimplementation of the shell quoting and aliasing features.
For example, if you invoke an alias on the remote machine
that resolves to a
sudo command, or you run a script
sudo command in it,
tsshbatch has no way to
determine what you're trying to do. For complex
applications, it's best to write a true shell script, push
it all the machines in question via
-P, and then have
tsshbatch remotely invoke it with
sudo myscript or
As always, the best way to figure out what the program
thinks you're asking for is to run it in test mode and look
at the diagnostic output.
Precedence Of Authentication Options
tsshbatch supports these various authentication options in a
particular heirarchy using a "first match wins" scheme. From highest
to lowest, the precedence is:
- Key exchange
- Forced prompting for name via -N. Notice this cancels any
previously requested key exchange authentication.
- Command Line/$TSSHBATCH environment variable sets name
- Name picked up from $USER (Default behavior)
If you try to use Key Exchange and
tsshbatch detects a command
sudo, it will prompt you for a password anyway.
This is because
sudo requires a password to promote privilege.
-P options specify file
respectively. Both are followed by a quoted file transfer
specification in the form:
Note that this means the file will always be stored under its original
name in the destination directory. Renaming isn't possible during
tsshbatch always does
PUTs then any
outstanding command (if any) at the end of the command line. This
permits things like renaming on the remote machine after a
tsshbatch.py -P "foo ./" -i hostlist mv -v foo foo.has.a.new.name
GETs are a bit of a different story because you are retrieving a
file of the same name on every host. To avoid having all but the last
one clobber the previous one,
tsshbatch makes forces the files you
GET to be uniquely named by prepending the hostname and a "-" to
the actual file name:
tsshbatch.py -H myhost -G "foo ./"
This saves the file
myhost-foo in the
./ on your a local
These commands do not recognize any special directory shortcut symbols
~/ like the shell interpreter might. You must name file and
directory locations using ordinary pathing conventions. You can put
as many of these requests on the command line as you like to enable
PUTs of multiple files. You cannot, however, use
filename wildcards to specify multi-file operations.
You can put multiple
PUTs on the command line for the
same file. They do not override each other but are cummulative. So
tsshbatch.py -P"foo ./" -P"foo /tmp" ...
Would put local file
foo in both
/tmp on each host
specified. Similarly, you can specify multiple files to
remote hosts and place them in the same local directory:
tsshbatch.py -G"/etc/fstab ./tmp" -G"/etc/rc.conf ./tmp" ...
You may also put file transfer specifications into a command file via
.putfile directives. This is handy when you
have many to do and don't want to clutter up the command line. Each
must be on its own line in the command file and in the same form as if
it were provided on the command line:
.getfile /path/to/srcfile destdir # This will get a file
.putfile /path/to/srcfile destdir # This will put a file
File transfers are done in the order they appear. For instance, if
you have a file transfer specification on the command line and then
make reference to a command file with a file transfer specification in
it, the one on the command line gets done first.
Keep in mind that
tsshbatch always processes file
transfers before executing any commands, no matter what
order they appear in the command file. If you have this in a
.putfile "./myfile /foo/bar/baz/"
The file will be transferred before the
gets run. This can be counterintuitive. It's therefore
recommended that you put your file transfers into a single
.include it as the first thing in your
command file to make it obvious that these will be run first.
tsshbatch aborts if any file transfer fails. This is
unlike the case of failed commands which are reported but do not
abort the program. The rationale' for this is that you may be doing
both file transfer and command execution with a single
invocation, and the commands may depend on a file being transfered
If you are sure no such problem exists, you can use the
to disable abort-after-failure semantics on file transfer. In this
case, file transfer errors will be reported, but
continue on to the next transfer request.
tsshbatch does preserve permissions when transferring files.
Obviously, for this to work, the destination has to be writable by the
ID you're logging in with.
The file transfer logic cannot cope with filenames that
contain spaces. The workaround is to either temporarily
rename them, or put them in a container like a tarball or
zip file and transfer that instead.
Both the command file and host file can be freely commented
# character. Everything from that character to the end
of that line is ignored. Similarly, you can use whitespace freely,
except in cases where it would change the syntax of a command or host
You may also include other files as you wish with the
filename directive anywhere in the command file or host file.
This is useful for breaking up long lists of things into smaller
parts. For example, suppose you have three host lists, one for each
major production areas of your network:
You might typically run different
tsshbatch jobs on each of these
sets of hosts. But suppose you now want to run a job on all of them.
Instead of copying them all into a master file (which would be
instantly obsolete if you changed anything in one of the above files),
you could create
hosts-all with this content:
that way if you edited any of the underlying files, the
hosts-all would reflect the change.
Similarly you can do the same thing with the command file to group
similar commands into separate files and include them.
tsshbatch does not enforce a limit on how deeply nested
.includes can be. An included file can include another file and
so on. However, if a circular include is detected, the program will
notify you and abort. This happens if, say, file1 includes file2,
file2 includes file3, and file3 includes file1. This would create an
infinite loop of includes if permitted. You can, of course, include
the same file multiple times, either in a single file or throughout
other included files, so long as no circular include is created.
The target of a
.include directive can also contain variable
references. Note, however, that references to builtin variables will
fail unless you have overriden them. Why? Because builtins don't get
defined until a host connection is attempted. This doesn't happen
until after all user defined variable processing and file includes
have been done. So:
.define MYINCLUDE = /some/fine/file # OK
.define MYINCLUDE = ! find /some/path -name includeski # OK
.include __HOSTNAME__ # Nope, not defined yet -
# tries to include file called '__HOSTNAME__'
.define __HOSTNAME__ ! hostname # Override the builtin
.include __HOSTNAME__ # OK
As a matter of keeping things simple, stick to user defined variables
as part of an
tsshbatch supports the ablity to search paths to find files you've
referenced. The search path for
cmdfiles is specified in the
$TSSHBATCHCMDS environment variable. The
path is specified in the
$TSSHBATCHHOSTS environment variable.
These are both in standard path delimited format for your operating
system. For example, on Unix-like systems these look like this:
And so forth.
These paths are honored both for any files you specify on the command
line as well as for any files you reference in a
directive. This allows you to maintain libraries of standard commands
and host lists in well known locations and
.include the ones you
tsshbatch will always first check to see if a file you've
specified is in your local (invoking) directory and/or whether it is a
fully qualified file name before attempting to look down a search
path. If a file exist in several locations, the first instance found
"wins". So, for instance, if you have a file called
somewhere in the path defined in
$TSSHBATCHHOSTS, you can override
it by creating a file of same name in your current working directory.
tsshbatch also checks for so-called "circular includes" which
would cause an infinite inclusion loop. It will abort upon
discovering this, prior to any file transfers or commands being
An Overview Of Variables
As you become more sophisticated in your use of
begin to see the same patterns of use over and over again. Variables
are a way for you to use "shortcuts" to reference long strings
without having to type the whole string in every time. So, for example,
instead of having to type in a command like this:
myfinecommand -X -Y -x because this is a really long string
You can just define variable like this:
.define __MYCMD__ = myfinecommand -X -Y -x because this is a really long string
From then on, instead of typing in that long command on the command line or in
a command file, you can just use
tsshbatch will substitute
the string as you defined it whenever it encounters the variable.
Variables can be used pretty much everwhere:
hostlistfiles or in the hostnames listed with
.define __MYDOMAIN__ = stage.mydomain.com
#.define __MYDOMAIN__ = prod.mydomain.com
Now you can switch
tsshbatch operation from stage to prod simply
by changing what is commented out at the beginning.
In file transfer specifications:
tsshbatch.py -xP"./fstab-__MYHOSTNAME__ ./" -i hostlist
tsshbatch.py -xG"/etc/__OSNAME__-release ./" -i hostlist
.define __SHELL__ = /usr/local/bin/bash
__SHELL__ -c myfinescript
A variable can have pretty much any name you like excepting
the use of metacharacters like
!. But if
you are not careful, you can cause unintended errors:
.define foo = Slop
When you run
tsshbatch it will then turn the server name
mySlopdserver.Slopds.com - probably not what you
So, it's a Really Good Idea (tm) to use some kind of naming
scheme to make variables names stand out and make them
unlikely to conflict accidentally with command- and host
Types Of Variables
tsshbatch has three different kinds of variables:
- User Defined Variables are the kind in the example above.
You, the user, define them as you wish in a command file or
- Execution Variables run any program or script of your choosing
(on the same machine you're running
tsshbatch) and assign
the results to a variable.
- Builtin Variables are variables the
defines. You can override their default values by creating
a User Defined Variable of the same name.
Where And When Do Variables Get Processed?
User Defined and Execution Variables are defined in either a
host file or command file.
Builtin Variables are defined within
tsshbatch itself unless you
User Defined Variables are all read in and then used. If you do
something like this:
.define __FOO__ = firstfoo
.define __FOO__ = secondfoo
You'll get an output of ...
secondfoo! Why? Because before
tsshbatch tries to run anything, it has to process all the
cmdfiles, host file, and the command line content. So,
before we ever get around to doing an
echo __FOO__ on some host,
the second definition of __FOO__ has been read in ... and last
Execution Variables are like User Defined Variables. They get
processed a single time at the time they're read in from a
command file or host file.
Builtin Variables get evaluated every time ``tsshbatch`` prepares to
connect to a new host (unless you've overriden them). That way, the
most current value for them is available for use on the next host.
Keep in mind that
tsshbatch isn't a programming language. It's
"variables" are simple string substitutions with "last one wins"
semantics. There is no notion of scope, for example. If you define
the same variable in, say, a command file and also in the
host file, the latter will "win". Why? Because
hostlistfiles are always read in after any
Finally, variable references in a definition are ignored. Say you
do this in a command file:
.define __CLEVER __ = __REALLYCLEVER__
.define __REALLYCLEVER__ = Not That Smart
You will get this output,
__REALLYCLEVER__! Why? Because, the
variable references on the right side of a definition statement are
never replaced. This is a concious design choice to keep variable
definition and use as simple and obvious as possible. Allowing such
"indirect" definitions opens up a treasure trove of maintenance pain
you really want to avoid. Trust us on this one.
tsshbatch allows you to define variables which will then be used
to replace matching strings in
file transfer specifications. For example, suppose you have this in a
At runtime, the program will actually connect to
host2.my.domain.com, and so on. This
allows for ease of modularization and maintenance of your files.
Similarly, you might want define
MYCMD=some_long_string so you
don't have to type
some_long_string over and over again in a
There are some "gotchas" to this:
The general form of a variable definition is:
.define name = value
You have to have a name but the value is optional.
FOO= simply replaces any subsequent
FOO strings with
nothing, effectively removing them.
= symbols to the right of the one right after
just considered part of the variable's value.
Whitespace around the
= symbol is optional but allowed.
Variables are substituted in the order they appear:
.define LS = ls -alr
LS /etc # ls -alr /etc
.define LS = ls -1
LS /foo # ls -1 /foo
Variable names and values are case sensitive.
Variables may be defined in either
hostlistfiles but they are visible to any subsequent file
that gets read. For instance,
cmdfiles are read before any
hostlistfiles. Any variables you've defined in a command file
that happen to match a string in one of your hostnames will be
This is usually not what you want, so be careful. One way to
manage this is to use variables names that are highly unlikely to
ever show up in a hostname or command. That way your commands and
hostnames will not accidentally get substrings replaced with
variable values. For example, you might use variable names like
Variable substitution is also performed on any host names
or commands passed on the command line.
Execution Variables are actually a special case of User Defined
Variables. That is, they are evaluated at the same time and in the
same manner as any other User Defined Variable. The difference is
that a User Defined Variable describes a literal string replacement.
But an Execution Variable runs a command, program, or script and
assigns the results to the variable.
For example, suppose you want create a file on many machines, and you
want that file to be named based on who ran the
You might do this in a command file:
.define __WHOAMI__ = ! whoami
So, if ID
luser is running
tsshbatch, a file called
luser-Put_This_Here.txt will be created (or have its timestamp
updated) on every machine in the host file or named with
Notice it is the
! character that distinguishes an Execution
Variable from a User Defined Variable. It is this character that
tsshbatch, "Go run the command to the right of me and return
the results." The trailing space is optional and the definition could
be written as:
.define __WHOAMI__ = !whoami
If the command you specify returns multiple lines of output, it's up
to you to process it properly.
tsshbatch does no newline
stripping or other postprocessing of the command results. This can
make the output really "noisy".
tssbatch normally reports
a summary of the command and its results. But if you do something
.define __LS__ = ! ls -al
You will get a multiline summary of the command and then the actual
output - which is also multiline. This gets to be obnonxious pretty
quickly. You can make a lot of this go away with the
It's important to remember that the program you are invoking
runs on the same machine as
tsshbatch itself, NOT each
host you are sending commands to. In other words, just
like Builtin Variables, Execution Variables are locally
As noted previously, Builtin Variables are created by
itself. They are created for each new host connection so that things
like time, host number, and hostname are up-to-date.
As of this release,
tsshbatch supports the following Builtins:
|Date in YYYYMMDD format
|Date and time in YYYYMMDDHHMMSS format
|Full name of current host as passed to
|Count of host being processed, starting at 1
|Leftmost component of hostname as passed to
|User name used for remote login. For key auth, name of tsshbatch user.
|Time in HHMMSS format
Using Builtin Variables
There are times when it's convenient to be able to embed the name of
the current host in either a command or in a file transfer
specification. For example, suppose you want to use a single
tsshbatch to transfer files in a host-specific way.
You might name your files like this:
Now, all you have to do is this:
tsshbatch.py -xH "host 1 host2" -P "myfile.__HOSTNAME__ ./"
tsshbatch will substitute the name of the current host
in place of the string
__HOSTNAME__. (Note that these are
**double* underbars on each side of the string.*)
You can do this in commands (and commands within command files) as
tsshbatch.py -x hosts 'echo I am running on __HOSTNAME__'
Be careful to escape and quote things properly, especially from the
the command line, since
> are recognized by the shell as
There are two forms of host name substitution possible. The first,
__HOSTNAME__ will use the name as you provided it, either as an
-H or from within a host file.
__HOSTSHORT__, will only use the portion of the name
string you provided up to the leftmost period.
So, if you specify
__HOSTNAME__ will be
replaced with that entire string, and
__HOSTSHORT__ will be
replaced by just
Notice that, in no case does
tsshbatch do any DNS lookups to
figure this stuff out. It just manipulates the strings you provide as
__HOSTSHORT__ are like any other
symbol you might have specified yourself with
means you can override their meaning. For instance, say you're doing
tsshbatch.py -x myhosts echo "It is: __HOSTNAME__"
As you would expect, the program will log into that host, echo the
hostname and exit. But suppose you don't want it to echo something
else for whatever reason. You'd create a command file with this
.define __HOSTNAME__ = Really A Different Name
Now, when you run the command above, the output is:
It is: Really A Different Name
In other words,
.define has a higher precedence than the
preconfigured values of
tsshbatch defaults to a medium level of reporting as it runs.
This includes connection reporting, headers describing the command
being run on every host,and the results written to
stdout. Each line of reporting output begins with
help you parse through the output if you happen to be writing a
program that post-processes the results from
This output "noise" is judged to be right for most applications of the
program. There are times, however, when you want more- or less
"noise" in the output. There are several
tsshbatch options that
These options only affect reporting of
commands you're running. They do not change the output of file
transfer operations. They also do not change error reporting, which
is always the same irrespective of current noise level setting.
-q or "quiet" mode, reduces the amount of output noise in
two ways. First, it silences reporting each time a successful
connection is made to a host. Secondly, the command being run
isn't reported in the header. For example, normally, running
ls -l is reported like this:
---> myhost: SUCCESS: Connection Established
---> myhost (stdout) [ls -l]:
---> myhost (stderr) [ls -l]:
In quiet mode, reporting looks like this:
---> localhost (stdout):
---> localhost (stderr):
The main reason for this is that some commands can be very long.
With execution variables, it's possible to create commands that
span many lines. The quiet option gives you the ability to
suppress echoing these long commands for each and every host
in your list.
-y or "noisy" mode, produces normal output noise but
also replicates the hostname and command string for
every line of output produced. For instance,
might normally produce this:
---> myhost: SUCCESS: Connection Established
---> myhost (stdout) [ls -1]:
But in noisy mode, you see this:
---> myhost: SUCCESS: Connection Established ---> myhost (stdout) [ls -1]:
[myhost (stdout) [ls -1]] backups
[myhost (stdout) [ls -1]] bin
Again, the purpose here is to support post-processing where you might
want to search through a large amount of output looking only for
results from particular hosts or commands.
-s or "silent" mode returns only the results from running the
commands. No headers or descriptive information are produced. It's
more-or-less what you'd see if you logged into the host and ran the
command interactively. For instance,
ls -l might look like this:
drwxr-xr-x 2 splot splot 4096 Nov 5 14:54 Desktop
drwxrwxr-x 39 splot splot 4096 Sep 9 14:57 Dev
drwxr-xr-x 3 splot splot 4096 Jun 14 2012 Documents
The idea here is to use silent mode with the various variables
described previously to customize your own reporting output. Imagine
you have this in a command file and you run
tsshbatch in silent
.define __USER__ = ! echo $USER
echo "Run on __HOSTNAME__ on __DATE__ at __TIME__ by __USER__"
You'd see output along these lines:
Run on myhost on 20991208 at 141659 by splot
Linux myhost 3.11.0-12-generic #19-Ubuntu SMP Wed Oct 9 16:20:46 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux
Comments can go anywhere.
.include must be the first
non-whitespace text on the left end of a line. If you do this in a
foo .include bar
tsshbatch thinks you want to run the command
foo with an
.include bar. If you do it in a host file,
the program thinks you're trying to contact a host called
.include bar. In neither case is this likely to be quite what you
had in mind. Similarly, everything to the right of the directive is
considered its argument (up to any comment character).
Whitespace is not significant at the beginning or end of a line but
it is preserved within
arguments as well as within commmand definitions.
Strictly speaking, you do not have to have whitespace after a
directive. This is recognized:
But this is strongly discouraged because it's really hard to read.
tsshbatch writes the
stdout of the remote host(s) to
stdout on the local machine. It similarly writes remote
stderr output to the local machine's
stderr. If you wish to
stderr output, either redirect it on your local command
line or use the
-e option to turn it off entirely. If you want
everything to go to your local
stdout, use the
You must have a reasonably current version of Python 2.x installed.
It almost certainly will not work on Python 3.x because it uses the
commands module. This decision was made to make the
program as backward compatible with older versions of Python as
possible (there is way more 2.x around than there is 3.x).
If your Python installation does not install
have to install it manually, since
tsshbatch requires these
libraries as well.
tsshbatch has been run extensively from Unix-like systems (Linux,
FreeBSD) and has had no testing whatsoever on Microsoft Windows. If
you have experience using it on Windows, do please share with the
class using the email address below. While we do not officially
support this tool on Windows, if the changes needed to make it work
properly are small enough, we'd consider updating the code
BUGS AND MISFEATURES
You will not be able to run remote
sudo commands if the host in
question enables the
Defaults requiretty in its
configuration. Some overzealous InfoSec folks seem to think this is
a brilliant way to secure your system (they're wrong) and there's
tsshbatch can do about it.
sudo is presented a bad password, it ordinarily prints a
string indicating something is wrong.
tsshbatch looks for this
to let you know that you've got a problem and then terminates
further operation. This is so that you do not attempt to log in
with a bad password across all the hosts you have targeted. (Many
enterprises have policies to lock out a user ID after some small
number of failed login/access attempts.)
However, some older versions of
sudo (noted on a RHEL 4 host
sudo 1.6.7p5) do not return any feedback when presented
with a bad password. This means that
tsshbatch cannot tell the
difference between a successful
sudo and a system waiting for
you to reenter a proper password. In this situation, if you enter a
bad password, the the program will hang. Why?
thinks nothing is wrong and waits for the
sudo command to
complete. At the same time,
sudo itself is waiting for an
updated password. In this case, you have to kill
start over. This typically requires you to put the program in
`Ctrl-Z in most shells) and then killing that job
from the command line.
There is no known workaround for this problem.
OTHER, SIMILAR PRODUCTS
It's always interesting to see how other people approach the same
problem. If you're interested in this general area of IT automation,
you may want to also look at
COPYRIGHT AND LICENSING
tsshbatch is Copyright (c) 2011-2016 TundraWare Inc.
tsshbatch-license.txt file in the
program distribution. If you install tsshbatch on a FreeBSD
system using the 'ports' mechanism, you will also find this file in
DOCUMENT REVISION INFORMATION
$Id: '8eb2a8e tundra Tue Oct 11 20:50:17 2016 -0500'
This document was produced with
You can find the latest version of this program at: