Extended shell linker for linking, processing and minifying shell code
Available from the zpkg repository:
wget -qO- https://zpkg.zawz.net/install.sh | sh
zpkg install lxshDownload the lxsh-linux-amd64.tar.gz archive, extract it,
and move the lxsh binary in a PATH folder (/usr/local/bin is the recommended).
wget https://github.com/zawwz/lxsh/releases/download/v1.3.0/lxsh-linux-amd64.tar.gz
tar -xvf lxsh-linux-amd64.tar.gz
sudo mv lxsh /usr/local/binSee Build.
lxsh implements special linking commands that are resolved at build time. These commands can be placed anywhere within the script like regular commands.
%include: allows to insert file contents%resolve: allows to execute a shell command and insert its output
See
lxsh --help-commandsfor more details
Reduce code size to a minimum without changing functionality with the -m option.
This option should be safe to use in any situation, if this option changes behavior please report a bug
- removes any unnecessary separator character between arguments/commands
- removes
;;from the last value in a case - removes unnecessary quotes on arguments
- transforms unnecessary manipulations (e.g.
${VAR}) into simple variable call - brace blocks or subshells with a single command will be replaced by said command
- reduces level 1
$()subshells to use backticks - escaped dollarsigns are un-escaped
These features only apply if they won't change behavior, for instance removal of an unnecessary manipulation will not be made if the following character could expand the variable name
The script can be further minified by altering code elements. This can cause some change in execution behavior if you are not careful.
Variable names can be minified with --minify-var,
use --exclude-var to exclude variables from being minified (for example environment config).
Function names can be minified with --minify-fct,
use --exclude-fct to exclude functions from being minified.
Unused functions and variables can be removed with --remove-unused.
Use -M to enable all of these minifying features (you still have to specify --exclude options when needed)
Some bash specific features can be translated into POSIX shell code.
The following bash features can be debashified:
<()and>()process substitutions<<<herestring>&,&>and&>>output redirects[[ ]]conditions- indexed arrays and associative arrays (+ their
declareandtypesetdefinitions) $RANDOM- substring variable manipulation (
${VAR:N:M}) - variable substitution (
${!VAR}) - search replace manipulation (
${VAR/s/a/b})
- Removes dependency on bash and makes a script more portable.
- In some cases it can also provide improved performance given that some more minimalist shells like
dashhave better performance.- this doesn't always apply for all situations, make sure to verify through testing
Debashifying of $RANDOM assumes /dev/urandom exists and provides proper randomness.
The debashified $RANDOM generates numbers in range 0:65535 instead of 0:32767.
Debashified calls of $RANDOM have major performance loss
The debashifying of process substitution assumes that /dev/urandom will exist and will provide proper randomness.
Temporary files with random names are used to create named pipes for the commands in the substitution.
There may be some slight performance loss on the creation of said process subtitution.
Indexed arrays and associative arrays are detected on parse instead of runtime.
By default if an array operator is found, it is assumed to be an indexed array,
and associative arrays are detected through the use of declare (or typeset).
In cases where there is ambiguity, the result upon execution might be undesired.
To avoid such ambiguities, put the
declarestatement of a variable first of all, and don't mix and match different types on the same variable name
Getting the value of an array without index will give the full value instead of the first value.
To avoid such situation, always get values from an index in your array
Arrays are stored as strings. Indexed arrays are delimited by tabs and associative arrays by newlines, This means inserting values containing these characters will have undesired behavior.
Debashified arrays have substantially reduced performance.
Where bash would present proper errors upon incorrectly accessing arrays, these features will continue working with undesired behavior.
To avoid this, make sure to never access incorrect values
Array argument with [@] does not expand into the desired multiple arguments.
Debashifying a substring manipulation on a variable containing a newline will not work correctly
If you use the #!/usr/bin/lxsh shebang, you can use special lxsh-defined commands.
To list such commands, see lxsh --help-extend-fcts
You can use prefixes in singlequote strings to apply processing to the string contents.
To use string processors, prefix the string content with a line in the form of #<PROCESSOR>.
Example:
sh -c '#LXSH_PARSE_MINIFY
printf "%s\n" "Hello world!"'As of now only the processor LXSH_PARSE_MINIFY is implemented, but more may come later
By default lxsh outputs generated shell code to stdout.
You can use the -o option to output to a file and make this file directly executable.
The resulting script is not dependent on lxsh
Directly execute an extended lxsh script with either
-eoption- shebang is lxsh
Direct execution introduces direct dependency on lxsh and code parsing overhead, therefore it should be avoided in production environments.
You can list all calls of variables, functions or commands with --list-* options
Depends on ztd
Use make -j to build.
You can use environment variables to alter some aspects:
- DEBUG: when set to
truewill generate a debug binary with profiling - RELEASE: when set to
true, the version string will be generated for release format - STATIC: when set to
truewill statically link libraries
The full POSIX syntax is supported and should produce a functioning result.
Most bash syntax is also supported, but not all.
- Extended globs (
*()) are not supported (())is parsed as subshells- Unsetting functions can have undesired effects