process

Creates a child process. Takes a command (vector of strings or objects that will be turned into strings) and optionally a map of options. Returns: a record with: - `:proc`: an instance of `java.lang.Process` - `:in`, `:err`, `:out`: the process's streams. To obtain a string from `:out` or `:err` you will typically use `slurp` or use the `:string` option (see below). Slurping those streams will block the current thread until the process is finished. - `:cmd`: the command that was passed to create the process. - `:prev`: previous process record in case of a pipeline. The returned record can be passed to `deref`. Doing so will cause the current thread to block until the process is finished and will populate `:exit` with the exit code. Supported options: - `:cmd`: a vector of strings. A single string can be tokenized into a vector of strings with `tokenize`. Overrides the variadic `args` argument. - `:in`, `:out`, `:err`: objects compatible with `clojure.java.io/copy` that will be copied to from the process's corresponding stream. May be set to `:inherit` for redirecting to the parent process's corresponding stream. Optional `:in-enc`, `:out-enc` and `:err-enc` values will be passed along to `clojure.java.io/copy`. For redirecting to Clojure's `*in*`, `*out*` or `*err*` stream, set the corresponding option accordingly. The `:out` and `:err` options support `:string` for writing to a string output and `:bytes` for writing to a byte array. You will need to `deref` the process before accessing the string or byte array via the process's `:out`. To redirect `:err` to `:out`, specify `:err :out`. For writing output to a file, you can set `:out` and `:err` to a `java.io.File` object, or a keyword: - `:write` + an additional `:out-file`/`:err-file` + file to write to the file. - `:append` + an additional `:out-file`/`:err-file` + file to append to the file. To discard `:out` or `:err`, use `:discard` - `:prev`: output from `:prev` will be piped to the input of this process. Overrides `:in`. - `:inherit`: if true, sets `:in`, `:out` and `:err` to `:inherit`. - `:dir`: working directory. - `:env`, `:extra-env`: a map of environment variables. See [Add environment](/README.md#add-environment). - `:escape`: function that will applied to each stringified argument. On Windows this defaults to prepending a backslash before a double quote. On other operating systems it defaults to `identity`. - `:pre-start-fn`: a one-argument function that, if present, gets called with a map of process info just before the process is started. Can be useful for debugging or reporting. Any return value from the function is discarded. Map contents: - `:cmd` - a vector of the tokens of the command to be executed (e.g. `["ls" "foo"]`) - `:shutdown`: shutdown hook, defaults to `nil`. Takes process map. Typically used with `destroy` or `destroy-tree` to ensure long running processes are cleaned up on shutdown. The shutdown hook is executed as soon as the child process ends. - `:exit-fn`: a function which is executed upon exit. Receives process map as argument. Only supported in JDK11+.