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Format command line options

Source: R/cmd_options.R
cmd_options.Rd

Helper function to format options for command line calls. The function accepts key-value pairs where the parameter name is the name of the option and the parameter value is the value of the option. Arguments are formatted according to the following rules:

  • If a value is TRUE, add parameter name as flag.

  • If a value is FALSE, do not add parameter name as flag.

  • If a value has length(x) > 1, collapse it as a CSV.

  • If a parameter name is missing, take the value as the flag name.

  • If a parameter name is given, replace underscores with hyphens.

Usage

cmd_options(..., use_double_hyphens = FALSE)

Arguments

...

Key-value pairs of command line options.

use_double_hyphens

If TRUE, uses double hyphens to designate non-abbreviated command line options and single-hyphens to designate abbreviated ones. If FALSE, always uses single hyphens. Defaults to FALSE as both Java and photon use single hyphens.

Value

A character vector of formatted command line options that can be used as input to system2 or run.

Examples

# converts R parameters to CMD options
# parameters for the ping command
cmd_options(n = 1, w = 5, "127.0.0.1")
#> [1] "-n"        "1"         "-w"        "5"         "127.0.0.1"

# sometimes, it is necessary to use double hyphens
# options for the docker ps command
cmd_options("ps", all = TRUE, format = "json", use_double_hyphens = TRUE)
#> [1] "ps"       "--all"    "--format" "json"    

# particularly useful together with photon
# the following options can be used for the `photon_opts` argument
# of photon$start()
cmd_options(cors_any = TRUE, data_dir = "path/to/dir")
#> [1] "-cors-any"   "-data-dir"   "path/to/dir"