To build jsh from source use the build.sh script.
To setup the environment install all dependencies in scripts/setup.sh and then from the jsh folder run scripts/build_google_test.
To begin execute build/jsh.
Inside of jsh there are two main components, processes and jobs.
A process is as you would expect, it is one binary that will be invoked on the given command line arguments it is passed.
A job is a series of processes that will run in sequence with one another.
Processes are chained together into jobs through the use of operators.
The exit keyword can be used to exit the jsh shell.
jsh supports setting environment variables through the keyword export.
Export commands must be of the form $export[whitespace][variable name]=[value]
Important
Variable names cannot contain the = character
Variable names cannot contain the { or } character
Variables and values cannot contain any whitespace
jsh supports using environment variables through substitution using the $ character.
To achieve substitution, the substitution must be of the form $[command part 1]${[environment variable name]}[command part 2].
In this case the characters from the $ to the } will be replaced by the value of the environment variable name.
In the case where the environment variable does not exist, it will be substituted for an empty string.
The environment variable $? will return the previous process' exit value.
Important
jsh does not support nested variable substitutions
If there is a $ character but the { and } are not properly placed (ie. the { is not immediately after the $), the substitution will fail and jsh will continue on to the next substitution in the input after the current substitutions $.
jsh will use the next } after the { to use as closing brace for the substitution
jsh supports 1000000 substitutions for one prompt
jsh does not allow the name of a environment variable to be ?
|: The|(pipe) operator chains together two commands such that the standard output of the first command becomes the standard input for the second command.&&: The&&(and) operator chains together two commands.
Important
Operator chaining must be used in the form $[first command and args][whitespace][operator][whitespace][second command and args]
In jsh there are two types of indirection, input and output.
Input Redirection:
Input redirection can be achieved by appending the < character followed by the relative or absolute filepath to the desired input file at any point in the command.
This files contents will then populate standard in for the first program in the job.
Output Redirection:
Output redirection can be achieved by appending the > character followed by the relative or absolute filepath to the desired output file at any point in the command.
This file will then be populated with contents of standard out from the last process in the job.
Important
Input and output redirection must be of the form $[arg1][whitespace][arg2][whitespace]...[< or >][whitespace][filepath][whitespace]...[whitespace][argn-1][whitespace][argn]
jsh does not support redirecting for standard error currently
In jsh pipes have precedence for IO redirection over redirection, such that if both redirection and pipes are utilized, the pipe will be written to instead of the file.
To contribute, please make github issues. These github issues will then be solved by the maintainer.