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|
let copyline input output =
let rec copy() = match input_char input with
| exception End_of_file ->
output_string output "<end of file>\n"
| char ->
output_char output char;
if char='\n' then () else copy()
in
copy();
flush output
let output_endline output str =
output_string output str;
output_char output '\n';
flush output
let output_env_var output env_var =
let value = match Sys.getenv_opt env_var with
| None -> "<no such variable>"
| Some v -> v
in
output_endline stdout value
let options =
[
("-i2o",
Arg.Unit (fun () -> (copyline stdin stdout)),
"copy one line from stdin to stdout");
("-i2e",
Arg.Unit (fun () -> (copyline stdin stderr)),
"copy one line from stdin to stderr");
("-o",
Arg.String (output_endline stdout),
"-o <txt> write <txt> plus newline to stdout");
("-e",
Arg.String (output_endline stderr),
"-e <txt> write <txt> plus newline to stderr");
("-v",
Arg.String (output_env_var stdout),
"-v <var> write value of environment variable <env> to stdout");
]
let report_bad_argument _arg =
output_endline stderr "<bad argument>"
let () =
set_binary_mode_in stdin true;
set_binary_mode_out stdout true;
set_binary_mode_out stderr true;
Arg.parse options report_bad_argument ""
|
