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termux
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Description

Termux add-on app for integration with Tasker.

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Termux:Tasker

Build status Join the chat at https://gitter.im/termux/termux

A Termux add-on app allowing

Termux
commands to be executed from Tasker and other plugin apps.

Contents

Installation

Check

termux-app
Installation for details before reading forward.

F-Droid

Termux:Tasker application can be obtained from

F-Droid
from here.

You do not need to download the

F-Droid
app (via the
Download F-Droid
link) to install Termux:Tasker. You can download the Termux:Tasker APK directly from the site by clicking the
Download APK
link at the bottom of each version section.

Github

Termux:Tasker application can be obtained on

Github
either from
Github Releases
for
>= v0.6
or from
Github Build
action workflows.

The APKs for

Github Releases
will be listed under
Assets
drop-down of a release. These are automatically attached when a new version is released.

The APKs for

Github Build
action workflows will be listed under
Artifacts
section of a workflow run. These are created for each commit/push done to the repository and can be used by users who don't want to wait for releases and want to try out the latest features immediately or want to test their pull requests.

The APKs for both of these are

debuggable
and are compatible with each other but they are not compatible with other sources.

Setup Instructions

Install Termux app (Mandatory)

The

Termux:Tasker
plugin requires Termux app to run the actual commands. You need to install it and start it at least once and have it install the required files for the plugin to start working. The Termux prefix directory
/data/data/com.termux/files/usr/
and Termux home directory
/data/data/com.termux/files/home/
must also exist and must have read, write and execute permissions
(0700)
for the plugin to work. The
$PREFIX/
is shortcut for the Termux prefix directory. The
~/
is a shortcut for the Termux home directory. Permissions and ownerships can be checked with the
stat 
command.

com.termux.permission.RUN_COMMAND
permission (Mandatory)

For

Termux:Tasker
version
>= 0.5
, the plugin host app will need to be granted the
com.termux.permission.RUN_COMMAND
permission to run ANY plugin commands. This is a security measure to prevent any other apps from running commands in
Termux
context which do not have the required permission granted to them. This is also required for the RUN_COMMAND Intent intent.

The Tasker app has requested the permission since

v5.9.3
, so you will need to update the app if you are using an older version. You can grant the permission using the
Permissions
activity in the
App Info
activity of your plugin host app. For
Tasker
you can grant it with:
Android Settings
->
Apps
->
Tasker
->
Permissions
->
Additional permissions
->
Run commands in Termux environment
.

If you do not grant the permission, you will likely get errors like

receiver com.termux.tasker.FireReceiver requires permission com.termux.permission.RUN_COMMAND which we don't have
when running the
Termux:Tasker
plugin action in
Tasker
. Note that, the
%errmsg
for missing permissions will not be set if you are using
Tasker
version
< 5.11.1.beta
and
Continue Task After Error
is enabled, only
%err
will be set to
1
. You can open the plugin configuration screen to detect missing permissions of the plugin host.

~/.termux/tasker/
Directory (Optional)

The

~/.termux/tasker/
directory stores the scripts that can be run with the plugin without setting
allow-external-apps
property to
true
if you do not want to use absolute paths. Open a non-root termux session and run the below command to create it and give it read, write and executable permissions
(0700)
. The
tasker
directory must have read permission, otherwise the plugin will not be able to read the script files and give errors like
No regular file found at path
for any script name entered in the
Executable
field of plugin configuration. The
tasker
directory of the script must also have executable permissions for the script to be allowed to execute.
mkdir -p /data/data/com.termux/files/home/.termux/tasker
chmod 700 -R /data/data/com.termux/files/home/.termux

allow-external-apps
property (Optional)

Termux:Tasker
version
>= 0.5
also allows commands to be run outside the
~/.termux/tasker/
directory by setting absolute paths in the
Executable
field of the plugin configuration ONLY if
allow-external-apps
property is set to
true
in
~/.termux/termux.properties
file. This is an added security measure. DO NOT set it to true if you have given a relatively untrusted app
com.termux.permission.RUN_COMMAND
permission, since it will be able to run arbitrary commands in termux or even root context (assuming termux has been granted root permissions) in the background without user intervention. The
~/.termux
directory must have read permission, otherwise the plugin will not be able to read the property values. This is also required for the RUN_COMMAND Intent intent.
  • Automatic You can use the one-liner commands below to set the desired value. The commands will append the desired value using

    echo
    command to the file if the file doesn't exist or the property doesn't exist in the file, otherwise it will
    sed
    replace any existing values of the key with the desired value.

    To set

    allow-external-apps
    property to
    true
    .
    value="true"; key="allow-external-apps"; file="/data/data/com.termux/files/home/.termux/termux.properties"; mkdir -p "$(dirname "$file")"; chmod 700 "$(dirname "$file")"; if ! grep -E '^'"$key"'=.*' $file &>/dev/null; then [[ -s "$file" && ! -z "$(tail -c 1 "$file")" ]] && newline=$'\n' || newline=""; echo "$newline$key=$value" >> "$file"; else sed -i'' -E 's/^'"$key"'=.*/'"$key=$value"'/' $file; fi
To set `allow-external-apps` property to `false`.  
    value="false"; key="allow-external-apps"; file="/data/data/com.termux/files/home/.termux/termux.properties"; mkdir -p "$(dirname "$file")"; chmod 700 "$(dirname "$file")"; if ! grep -E '^'"$key"'=.*' $file &>/dev/null; then [[ -s "$file" && ! -z "$(tail -c 1 "$file")" ]] && newline=$'\n' || newline=""; echo "$newline$key=$value" >> "$file"; else sed -i'' -E 's/^'"$key"'=.*/'"$key=$value"'/' $file; fi
  • Manual You can do it manually by running the below commands to open the
    nano
    text editor in the terminal. Then add/update a line
    allow-external-apps=true
    to set the property to
    true
    , and press
    Ctrl+o
    and then
    Enter
    to save and
    Ctrl+x
    to exit.
    file="/data/data/com.termux/files/home/.termux/termux.properties";
    mkdir -p "$(dirname "$file")";
    nano "$file"

Draw Over Apps
permission (Optional)

For android

>= 10
there are new restrictions that prevent activities from starting from the background. This prevents the background
TermuxService
from starting a terminal session in the foreground and running the commands until the user manually clicks
Termux
notification in the status bar dropdown notifications list. This only affects plugin commands that are to be executed in a terminal session and not the background ones.
Termux
version
>= 0.100
requests the
Draw Over Apps
permission so that users can bypass this restriction so that commands can automatically start running without user intervention. You can grant
Termux
the
Draw Over Apps
permission from its
App Info
activity
Android Settings
->
Apps
->
Termux
->
Advanced
->
Draw over other apps
.

Usage

Tasker

  1. Create a new
    Action
    in a
    Task
    .
  2. In the resulting
    Select Action Category
    dialog, select
    Plugin
    .
  3. In the resulting
    Action Plugin
    dialog, select
    Termux:Tasker
    .
  4. Click the edit button to edit the configuration.
  5. Run the task once the configuration is complete. ##

Plugin Configuration

The plugin configuration activity can be started by plugin host apps to configure the plugin to define what commands should be run and in which mode.

The text fields support plugin host app local variables (all lowercase) like

%executable
,
%arguments
,
%workdir
,
%stdin
, etc and you may use multiple variables in a single field.

Executable

The

Executable
text field defines the executable that needs to be run. It can either be set to a file in
~/.termux/tasker/
directory or to an absolute path if
allow-external-apps
property is set to
true
(check Setup Instructions). Absolute paths can be like
/data/data/com.termux/files/usr/bin/bash
. The
$PREFIX/
and
~/
prefixes are also supported, like
$PREFIX/bin/bash
or
~/some-script
.

Execute permissions will automatically be set for the executable file if it exists inside the

~/.termux/tasker/
directory when the plugin action is run. It is the user's responsibility to set read and execute permissions for the executable file if it exists outside the
~/.termux/tasker/
directory. That can be done by running the command
chmod 700 "/path/to/executable"
from a terminal session before running the plugin action.

Arguments

The

Arguments
text field defines the argument that will be passed to the executable. For
Termux:Tasker
version
>= 0.5
, arguments will be processed just like there are if commands are run in a shell like bourne shell. It uses ArgumentTokenizer to parse the arguments string.

Arguemnts are split on whitespaces unless quoted with single or double quotes. Double quotes and backslashes can be escaped with backslashes in arguments surrounded with double quotes.

Any argument surrounded with single quotes is considered a literal string. However, if an argument itself contains single quotes, then they will need to be escaped properly. You can escape them by replacing all single quotes

'
in an argument value with
'\''
before passing the argument surrounded with single quotes. So an argument surrounded with single quotes that would have been passed like
'some arg with single quote ' in it'
will be passed as
'some arg with single quote '\'' in it'
. This is basically 3 parts
'some arg with single quote '
,
\'
and
' in it'
but when processed, it will be considered as one single argument with the value
some arg with single quote ' in it
that is passed to the executable.

For

Tasker
, you can use the
Variable Search Replace
action on an
%argument
variable to escape the single quotes. Set the
Search
field to one single quote
'
, and enable
Replace Matches
toggle, and set
Replace With
field to one single quote, followed by two backslashes, followed by two single quotes
'\\''
. The double backslash is to escape the backslash character itself.

Working directory path

The

Working directory path
text field for
Termux:Tasker
version
>= 0.5
defines the working directory that should be used while running the command. The directory must be readable by the termux app. It is the user's responsibility to create the directory if its outside the
~/
directory for version
< 0.6
and
/data/data/com.termux/files
directory for version
>= 0.6
. That can be done by running the command
mkdir -p "/path/to/workdir"
from a terminal session before running the plugin action. The
$PREFIX/
and
~/
prefixes are also supported, like
$PREFIX/some-directory
or
~/some-directory
.

Stdin

The

Stdin
text field for
Termux:Tasker
version
>= 0.6
can be used to pass scripts via standard input (
stdin
), like a
bash
script to the
$PREFIX/bin/bash
shell and a
python
script to the
$PREFIX/bin/python
shell or any other commands. This allows scripts to be defined in the plugin host app instead of defining physical script files in
~/.termux/tasker/
directory. Check Defining Scripts In Plugin Host App for details.

Note that if passing script via

stdin
, do not pass arguments, since it will fail depending on shell, at least will for
bash
.

The max supported length of a script is

45K
characters taking into consideration the Tasker plugin bundle limits of
100KB
when its stored in a
Parcel
. On Android
7-11
, the
String
characters are stored in Parcel as
UTF-16
, i.e
2
bytes. So we use
10KB
for rest of the plugin configuration data and half of the remaining (
90KB
) for storing the script.

Terminal Session Action

The

Terminal Session Action
text field for
Termux:Tasker
version
>= 0.6
defines what should happen when a foreground session command is received for the
Termux
. The user can define whether the new session should be automatically switched to or if existing session should remain as the current session. The user can also define if foreground session commands should open the
TermuxActivity
or if they should run in the "background" in the Termux notification. The user can click the notification to open the sessions. The valid values are defined by
TermuxConstants.TERMUX_APP.TERMUX_SERVICE.VALUE_EXTRA_SESSION_ACTION_*
, currently, between
0
and
3
.

Custom Log Level

The

Custom Log Level
text field for
Termux:Tasker
version
>= 0.6
defines the log level for background commands that should be used by
Termux
.

By default Termux only logs command

stdout
and
stderr
to
logcat
if user has set log level to
VERBOSE
in Termux app settings (not
Termux:Tasker
). However, if command outputted too much data to
logcat
, then
logcat
clients like in Android Studio would crash.

So one can pass a custom log level that is

>=
to the log level set it Termux app settings where (
OFF=0
,
NORMAL=1
,
DEBUG=2
,
VERBOSE=3
) for custom behaviour. If you pass
0
, it will completely disable logging. If you pass
1
, logging will only be enabled if log level in termux settings is
NORMAL
or higher. If custom log level is not passed, then default behaviour will remain and log level in Termux app settings must be
VERBOSE
or higher for logging to be enabled. Note that the log entries will still be logged with priority
Log.VERBOSE
regardless of log level, i.e
logcat
will have
V/
.

The entries

logcat
component will be
TermuxCommand
. For output at
stdout
, the entry format is
[-stdout] ...
and for the output at
stderr
, the entry format is
[-stderr] ...
. The
 will be the process id (
pid
) as an integer that was started by Termux for the executable. For example:
V/TermuxCommand: [66666-stdout] ...
.
Using
Custom Log Level
to send commands to Tasker

Instead of using am command to send messages back to Tasker, you can use Tasker Logcat Entry profile event to listen to messages from Termux at both stdout and stderr. This might be faster than am command intent systems or at least possibly more convenient in some use cases.

So setup a profile with the Component value set to TermuxCommand and Filter value set to -E 'TermuxCommand: \[[0-9]+-((stdout)|(stderr))\] message_tag: .*' and enable the Grep Filter toggle so that entry matching is done in native code. Check Tasker Logcat Info documentation for details. Also enable Enforce Task Order in profile settings and set collision handling to Run Both Together so that if two or more entries are sent quickly, entry task is run for all. Tasker currently (v5.13.16) is not maintaining order of entry tasks despite the setting.

Then start a Termux:Tasker plugin action with custom log level 1 (assuming current log level is NORMAL) and you should be able to receive the entries for whatever you send to stdout and stderr in your script that starts with message_tag: as %lc_text in entry task of tasker Logcat Entry profile. You can remove the prefix from the %lc_text variable with Variable Search Replace action. Set the Search field to TermuxCommand: \[[0-9]+-((stdout)|(stderr))\] message_tag: , and enable Replace Matches toggle, and leave Replace With empty.

Execute in a terminal session

The

Execute in a terminal session
toggle defines whether the commands will be run in the background or in a foreground terminal session.

If the toggle is enabled, a new terminal session will open up automatically in the foreground and commands will be run inside it. Result of commands is not returned to the plugin host app for version

< 0.6
. For version
>= 0.6
, result will be returned in
%stdout
and
%result
variables. The
%stdout
variable will only contain the session transcript and will contain both
stdout
and
stderr
combined, basically anything sent to the the pseudo terminal
/dev/pts
, including
PS1
prefixes for interactive sessions. For foreground commands that exited with failure will require Termux app version
>= 0.118
for sessions to automatically close without waiting for user to press enter.

If the toggle is not enabled, then commands are run in the background and result of commands is returned to the plugin host app in

%stdout
,
%stderr
and
%result
variables.

Check Setup Instructions for android

>= 10
restrictions that will prevent the commands from automatically starting unless notification is clicked.

Wait for result for commands

The

Wait for result for commands
toggle for
Termux:Tasker
version
>= 0.6
defines whether the plugin action should wait for result of commands. It will apply to both foreground session and background commands. Check Plugin Variables for details.

Check Templates section for templates that can be used for various configurations.

Plugin Variables

Depending on plugin configuration, the following variables may be returned.

  • %stdout
    containing
    stdout
    of commands.
  • %stdout_original_length
    containing original length of
    stdout
    .
  • %stderr
    containing
    stderr
    of commands.
  • %stderr_original_length
    containing original length of
    stderr
    .
  • %result
    containing
    exit code
    of commands. The
    exit code
    0
    often means success and anything else is usually a failure of some sort.
  • %err
    containing
    exit code
    of plugin action. This will be set only if running the action itself failed like missing permissions or invalid configuration. This may be set by the plugin host app or the plugin. This will not be set if plugin action succeeded.
  • %errmsg
    containing the error message of why the plugin action failed if
    %err
    is set.  

If the timeout value of the plugin action is set to

0
or
None
(slider to extreme left in Tasker), then no variables will be returned, regardless of whether commands need to be run in a foreground terminal session or in background. Even
%errmsg
will not be set to notify of any errors while running the plugin action since plugin host app will not wait for the plugin to return any variables. This is important for cases like if
allow-external-apps
is not set to
true
but an absolute path outside
~/.termux/tasker/
directory is set as the
Executable
, in which case the plugin action will appear to have succeeded but no commands will execute.

If the timeout value of the plugin action is set to

>0
and
Wait for result for commands
toggle is enabled, then the result of commands will be returned in
%stdout
,
%stderr
(only background) and
%result
variables. The
%err
and
%errmsg
variables may also be set if the action failed. Note that if the timeout has passed by the time commands finish, the result of command variables will not be set in the plugin host app task and the action will exit with a timeout error, the
%err
variable will be set to
2
and
%errmsg
to
timeout
, at least in
Tasker
.

If the timeout value of the plugin action is set to

>0
and
Wait for result for commands
toggle is not enabled, then
%stdout
,
%stderr
and
%result
variables will not be returned. Only the
%err
and
%errmsg
variables may be set if the action failed.

The (new) default timeout is set to

10s
for all configurations. If you are running background commands that will likely take longer to run, then increase the timeout or set it to
Never
(slider to extreme right in Tasker). The plugin host app may still get killed by android if it keeps running for long time regardless of timeout value, check here for more info. Even if the commands are to be run in a foreground terminal session, do not set timeout to
0
but use
10s
instead, since with timeout
0
, plugin host app will not wait for any errors to be returned by the plugin in
%err
and
%errmsg
variables and continue the task and the user wouldn't know if any error occurred. Users who already have preexisting actions with the timeout set to
0
, like for foreground terminal session commands (considering previous default was
0
) should update their tasks and use the new default
10s
instead, just opening the configuration screen and returning should automatically do it.  

For

Termux:Tasker
version
>= 0.5
, the
%errmsg
,
%stdout
,
%stderr
and
%result
variables will also be automatically cleared whenever the action is run if timeout is greater than
0
to solve the issue of if multiple actions are run in the same task, then variables from previous action may still be set and get mixed in with current ones. For older versions, you can use a
Variable Clear
action in Tasker with
Pattern Matching
enabled and the
Name
field set to
%errmsg/%stdout/%stderr/%result
to clear all of them before each plugin action if multiple actions are run in a task or
Local Variable Passthrough
is enabled in Tasker.

The

%err
and
%errmsg
variables will mainly only be set for
Termux:Tasker
version
>= 0.5
. These will be set if there are errors like if an executable file is not found, or if
allow-external-apps
property is not set to
true
but an absolute path is specified as the executable.
Tasker
itself may set it too like if
Tasker
has not been granted the
com.termux.permission.RUN_COMMAND
permission when running the plugin action or if a timeout occurs, etc.

The

%err
and
%errmsg
variables must be stored in another variable with the
Variable Set
action right after the plugin action if they have to be checked and used later. The plugin host app like Tasker sets and clears
%err
for each action and it is only available in the next action. To check if and what they are set to, add a
Variable Clear
action for
%command_failed
variable before the plugin action, then add a
Variable Set
action after the plugin action for the
%command_failed
variable with the value
%err %errmsg
and
If
conditions
If %err Set OR If %errmsg Set
. Then you can just check
If %command_failed Set
afterward and flash it to notify the user or exit the task if necessary. Error checking should ideally also be done based on
%result
and optionally the
%stderr
variables before continuing the task.  

The

%stdout_original_length
and
%stderr_original_length
can be used to check if
%stdout
and
%stderr
were truncated by Termux app before sending them back to plugin host app in case they were too large and would have triggered
TransactionTooLargeException
. The
stdout
and
stderr
sent back will be truncated from the start to max
100KB
combined. The
errmsg
will also be truncated from end to max
25KB
. Check here and here for details.

Check Templates section for templates on how error and result variables should be handled for various configurations.

Templates

The templates were written for version

< 0.6
and currently have not been updated for version
>= 0.6
.

Tasker

  • Tasks
    • XML
      Download the Termux Tasker Plugin Basic Templates Task XML file to the android download directory. To download, right-click or hold the
      Raw
      button at the top after opening a file link and select
      Download/Save link
      or use
      curl
      from a termux shell. Then import the downloaded task file into Tasker by long pressing the
      Task
      tab button in Tasker home and selecting
      Import Task
      .

      curl -L 'https://github.com/termux/termux-tasker/raw/master/templates/plugin_hosts/tasker/Termux_Tasker_Plugin_Basic_Templates.tsk.xml' -o "/storage/emulated/0/Download/Termux_Tasker_Plugin_Basic_Templates.tsk.xml"
    • Taskernet
      Import
      Termux Tasker Plugin Basic Templates Task
      from
      Taskernet
      from here.

    Check Termux Tasker Plugin Basic Templates Task Info file for more info on the task.

  • Scripts
    To use the above task, you will also need to place the termuxtaskerbasicbashtest and termuxtaskerbasicpythontest scripts in
    ~/.termux/tasker/
    directory after following its Setup Instructions. They basically just print the first
    2
    args to
    stdout
    if only
    2
    args are received, otherwise exit with error.
1. Download the script files.  

- Download to `~/.termux/tasker/` directly from github using `curl` using a non-root termux shell.  

    `curl -L 'https://github.com/termux/termux-tasker/raw/master/templates/scripts/termux_tasker_basic_bash_test' -o "/data/data/com.termux/files/home/.termux/tasker/termux_tasker_basic_bash_test"`  

    `curl -L 'https://github.com/termux/termux-tasker/raw/master/templates/scripts/termux_tasker_basic_python_test' -o "/data/data/com.termux/files/home/.termux/tasker/termux_tasker_basic_python_test"`  

- Download them manually to android download directory and then use `cat` to copy them to `~/.termux/tasker/` or manually do it with a [SAF file browser](#Creating-And-Modifying-Scripts).  

    `cat "/storage/emulated/0/Download/termux_tasker_basic_bash_test" &gt; "/data/data/com.termux/files/home/.termux/tasker/termux_tasker_basic_bash_test"`  

    `cat "/storage/emulated/0/Download/termux_tasker_basic_python_test" &gt; "/data/data/com.termux/files/home/.termux/tasker/termux_tasker_basic_python_test"`  
  1. Set executable permissions.

    chmod 700 "/data/data/com.termux/files/home/.termux/tasker/termux_tasker_basic_bash_test"

    chmod 700 "/data/data/com.termux/files/home/.termux/tasker/termux_tasker_basic_python_test"

To modify the scripts you can use nano.

nano "/data/data/com.termux/files/home/.termux/tasker/termux_tasker_basic_bash_test"
nano "/data/data/com.termux/files/home/.termux/tasker/termux_tasker_basic_python_test"

Termux needs to be granted

Storage
permission to allow it to access
/storage/emulated/0/Download
directory, otherwise you will get permission denied errors while running commands.

Creating And Modifying Scripts

You can create scripts in

~/.termux/tasker/
directory after following its Setup Instructions. Scripts can also be created elsewhere in Termux files directory but will require
allow-external-apps
to be set to
true
for the plugin to access them.

You can use

shell
based text editors like
nano
,
vim
or
emacs
to create and modify scripts.

nano "/data/data/com.termux/files/home/.termux/tasker/some_script"

You can also use

GUI
based text editor android apps that support
SAF
. Termux provides a Storage Access Framework (SAF) file provider to allow other apps to access its
~/
home directory. However, the
$PREFIX/
directory is not accessible to other apps. The QuickEdit or QuickEdit Pro app does support
SAF
and can handle large files without crashing, however, it is closed source and its pro version without ads is paid. You can also use Acode editor or Turbo Editor if you want an open source app.

Note that the android default

SAF
Document
file picker may not support hidden file or directories like
~/.termux
which start with a dot
.
, so if you try to use it to open files for a text editor app, then that directory will not show. You can instead create a symlink for
~/.termux
at
~/termux_sym
so that it is shown. Use
ln -s "/data/data/com.termux/files/home/.termux" "/data/data/com.termux/files/home/termux_sym"
to create it.

Debugging

You can help debug problems like how arguments are being parsed by the plugin or if the plugin is even firing etc by setting appropriate

logcat
Log Level
in options menu (3 dots) in the plugin configuration screen or in Termux app settings ->
Termux:Tasker
->
Debugging
->
Log Level
. Note that whatever log level is set will affect the entire plugin app and all plugin actions and not just for the action whose configuration you used to set it. The setting only exists inside the configuration activity of actions because creating a separate launcher activity that would be shown in the list of apps in the launcher just for this setting doesn't seem worth it.
Log Level
defaults to
Normal
and log level
Debug
currently logs additional information. Its best to revert log level to
Normal
after you have finished debugging since private data may otherwise be passed to
logcat
during normal operation and moreover, additional logging increases execution time.

For information on how to view the

logcat
logs, check official android guide here.
Log Levels
  • Off
    - Log nothing
  • Normal
    - Start logging error, warn and info messages and stacktraces
  • Debug
    - Start logging debug messages
  • Verbose
    - Start logging verbose messages ##

Worthy Of Note

Arguments and Result Data Limits

There are limits on the arguments size you can pass to commands or the full command string length that can be run, which is likely equal to

131072
bytes or
128KB
for an android device defined by
ARG_MAX
but after subtracting shell environment size, etc, it will roughly be around
120-125KB
but limits may vary for different android versions and kernels. You can check the limits for a given termux session by running
true | xargs --show-limits
. If you exceed the limit, you will get exceptions like
Argument list too long
. You can manually cross the limit by running something like
$PREFIX/bin/echo "$(head -c 131072 < /dev/zero | tr '\0' 'a')" | tr -d 'a'
, use full path of
echo
, otherwise the
echo
shell built-in will be called to which the limit does not apply since
exec
is not done.

Moreover, exchanging data between

Tasker
and
Termux:Tasker
is done using Intents, like sending the command and receiving result of commands in
%stdout
and
%stderr
. However, android has limits on the size of actual data that can be sent through intents, it is roughly
500KB
on android
7
but may be different for different android versions. The
Termux
app based on testing still sets a safe limit at
100KB
and will truncate any data higher than that. Check
%stdout_original_length
and
%stderr_original_length
in Plugin Variables section for details.

Basically, make sure any data/arguments you send to

Termux:Tasker
is less than
120KB
(or whatever you found) and any expected result sent back is less than
100KB
, but best keep it as low as possible for greater portability. If you want to exchange an even larger data between tasker and termux, use physical files instead.

The argument data limits also apply for the RUN_COMMAND Intent intent.

Termux Environment

Termux does not load the environment fully for external plugins or RUN_COMMAND Intent commands, like setting

LD_PRELOAD
, so any external scripts which do not have shebangs to full path to termux bin directory will not work if called from inside your plugin scripts, since
libtermux-exec.so
is not called since
LD_PRELOAD
isn't set and you will get
bad interpreter: No such file or directory
errors. Simply setting
LD_PRELOAD
will not work either without starting a new shell. So make sure to set the shebangs correctly for any external scripts you want to run from inside your plugin script. The correct shebangs for termux scripts are like
#!/data/data/com.termux/files/usr/bin/bash
for bash scripts instead of
#!/usr/bin/bash
used in common linux distros. You can also use termux-fix-shebang command on the external scripts before running them with the plugin to fix the shebangs automatically or use
tudo
/
sudo
mentioned below.
Defining Scripts In Plugin Host App

Any script files that need to be run need to be created in

~/.termux/tasker/
directory. It may get inconvenient to create physical script files for each type of command you want to run. These script files are also neither part of backups of plugin host apps like Tasker and require separate backup methods and nor are part of project configs shared with other people or even between your own devices, and so the scripts need to be added manually to the
~/.termux/tasker/
directory on each device.

To solve such issues and to dynamically define scripts of different interpreted languages inside your plugin host app like

Tasker
and to pass them to
Termux
as arguments instead of creating script files, you can either use
Stdin
plugin configuration field or use
tudo
or
sudo
.

The tudo script can be used for running commands in termux user context and the sudo script for running commands with super user (root) context, check their

script
command type. These scripts will also load the termux environment properly like setting
LD_PRELOAD
etc before running the commands. There are much more customizable then using
Stdin
and support things that aren't possible to be provided via the plugin.

License

Released under the GPLv3 license.

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