cat function Null safety
Concatenates files in paths
to stdout
The parameters are similar to the GNU cat utility.
Specify a log
for debugging or testing purpose.
Implementation
Future<int> cat(List<String> paths,
{String appName = '',
List<String>? log,
bool showEnds = false,
bool numberNonBlank = false,
bool showLineNumbers = false,
bool showTabs = false,
bool squeezeBlank = false,
bool showNonPrinting = false}) async {
var lineNumber = 1;
var returnCode = 0;
log?.clear();
if (paths.isEmpty) {
final lines = await _readStdin();
await _writeLines(lines, lineNumber, log, showEnds, showLineNumbers,
numberNonBlank, showTabs, squeezeBlank, showNonPrinting);
} else {
for (final path in paths) {
try {
final Stream<String> lines;
if (path == '-') {
lines = await _readStdin();
} else {
lines = utf8.decoder
.bind(File(path).openRead())
.transform(const LineSplitter());
}
lineNumber = await _writeLines(
lines,
lineNumber,
log,
showEnds,
showLineNumbers,
numberNonBlank,
showTabs,
squeezeBlank,
showNonPrinting);
} on FileSystemException catch (e) {
final String? osMessage = e.osError?.message;
final String message;
if (osMessage != null && osMessage.isNotEmpty) {
message = osMessage;
} else {
message = e.message;
}
returnCode = await printError(message, appName: appName, path: path);
} on FormatException {
returnCode = await printError('Binary file not supported.',
appName: appName, path: path);
} catch (e) {
returnCode =
await printError(e.toString(), appName: appName, path: path);
}
}
}
return returnCode;
}