diff --git a/cli/src/cli.rs b/cli/src/cli.rs
index c3e30d5172f057..04c2c468a4716d 100644
--- a/cli/src/cli.rs
+++ b/cli/src/cli.rs
@@ -2,11 +2,15 @@ use crate::{
     cluster_query::*, feature::*, inflation::*, memo::*, nonce::*, program::*, spend_utils::*,
     stake::*, validator_info::*, vote::*,
 };
-use clap::{value_t_or_exit, App, AppSettings, Arg, ArgMatches, SubCommand};
+use clap::{
+    crate_description, crate_name, value_t_or_exit, App, AppSettings, Arg, ArgMatches,
+    SubCommand, Shell, ArgGroup
+};
 use log::*;
 use num_traits::FromPrimitive;
 use serde_json::{self, Value};
 use solana_account_decoder::{UiAccount, UiAccountEncoding};
+use solana_cli_config::CONFIG_FILE;
 use solana_clap_utils::{
     self,
     fee_payer::{fee_payer_arg, FEE_PAYER_ARG},
@@ -53,8 +57,8 @@ use solana_sdk::{
 use solana_transaction_status::{EncodedTransaction, UiTransactionEncoding};
 use solana_vote_program::vote_state::VoteAuthorize;
 use std::{
-    collections::HashMap, error, fmt::Write as FmtWrite, fs::File, io::Write, str::FromStr,
-    sync::Arc, time::Duration,
+    collections::HashMap, error, fmt::Write as FmtWrite, fs::File, io::Write, io::stdout,
+    str::FromStr, sync::Arc, time::Duration,
 };
 use thiserror::Error;
 
@@ -949,6 +953,37 @@ pub fn parse_command(
                 signers: vec![],
             })
         }
+        ("completion", Some(matches)) => {
+            match matches.value_of("shell") {
+                Some("bash") =>
+                    get_clap_app(
+                        crate_name!(), crate_description!(),
+                        solana_version::version!()
+                    ).gen_completions_to("solana", Shell::Bash, &mut stdout()),
+                Some("fish") =>
+                    get_clap_app(
+                        crate_name!(), crate_description!(),
+                        solana_version::version!()
+                    ).gen_completions_to("solana", Shell::Fish, &mut stdout()),
+                Some("zsh") =>
+                    get_clap_app(
+                        crate_name!(), crate_description!(),
+                        solana_version::version!()
+                    ).gen_completions_to("solana", Shell::Zsh, &mut stdout()),
+                Some("powershell") =>
+                    get_clap_app(
+                        crate_name!(), crate_description!(),
+                        solana_version::version!()
+                    ).gen_completions_to("solana", Shell::PowerShell, &mut stdout()),
+                Some("elvish") =>
+                    get_clap_app(
+                        crate_name!(), crate_description!(),
+                        solana_version::version!()
+                    ).gen_completions_to("solana", Shell::Elvish, &mut stdout()),
+                _ => unreachable!() // This is safe, since we assign default_value
+            }
+            std::process::exit(0);
+        }
         //
         ("", None) => {
             eprintln!("{}", matches.usage());
@@ -2040,7 +2075,189 @@ where
     }
 }
 
-pub fn app<'ab, 'v>(name: &str, about: &'ab str, version: &'v str) -> App<'ab, 'v> {
+fn finalize_clap_app<'ab, 'v>(app: App<'ab, 'v>) -> App<'ab, 'v> {
+    app.arg({
+        let arg = Arg::with_name("config_file")
+            .short("C")
+            .long("config")
+            .value_name("FILEPATH")
+            .takes_value(true)
+            .global(true)
+            .help("Configuration file to use");
+        if let Some(ref config_file) = *CONFIG_FILE {
+            arg.default_value(config_file)
+        } else {
+            arg
+        }
+    })
+    .arg(
+        Arg::with_name("json_rpc_url")
+            .short("u")
+            .long("url")
+            .value_name("URL_OR_MONIKER")
+            .takes_value(true)
+            .global(true)
+            .validator(is_url_or_moniker)
+            .help(
+                "URL for Solana's JSON RPC or moniker (or their first letter): \
+                   [mainnet-beta, testnet, devnet, localhost]",
+            ),
+    )
+    .arg(
+        Arg::with_name("websocket_url")
+            .long("ws")
+            .value_name("URL")
+            .takes_value(true)
+            .global(true)
+            .validator(is_url)
+            .help("WebSocket URL for the solana cluster"),
+    )
+    .arg(
+        Arg::with_name("keypair")
+            .short("k")
+            .long("keypair")
+            .value_name("KEYPAIR")
+            .global(true)
+            .takes_value(true)
+            .help("Filepath or URL to a keypair"),
+    )
+    .arg(
+        Arg::with_name("commitment")
+            .long("commitment")
+            .takes_value(true)
+            .possible_values(&[
+                "processed",
+                "confirmed",
+                "finalized",
+                "recent", // Deprecated as of v1.5.5
+                "single", // Deprecated as of v1.5.5
+                "singleGossip", // Deprecated as of v1.5.5
+                "root", // Deprecated as of v1.5.5
+                "max", // Deprecated as of v1.5.5
+            ])
+            .value_name("COMMITMENT_LEVEL")
+            .hide_possible_values(true)
+            .global(true)
+            .help("Return information at the selected commitment level [possible values: processed, confirmed, finalized]"),
+    )
+    .arg(
+        Arg::with_name("verbose")
+            .long("verbose")
+            .short("v")
+            .global(true)
+            .help("Show additional information"),
+    )
+    .arg(
+        Arg::with_name("no_address_labels")
+            .long("no-address-labels")
+            .global(true)
+            .help("Do not use address labels in the output"),
+    )
+    .arg(
+        Arg::with_name("output_format")
+            .long("output")
+            .value_name("FORMAT")
+            .global(true)
+            .takes_value(true)
+            .possible_values(&["json", "json-compact"])
+            .help("Return information in specified output format"),
+    )
+    .arg(
+        Arg::with_name(SKIP_SEED_PHRASE_VALIDATION_ARG.name)
+            .long(SKIP_SEED_PHRASE_VALIDATION_ARG.long)
+            .global(true)
+            .help(SKIP_SEED_PHRASE_VALIDATION_ARG.help),
+    )
+    .arg(
+        Arg::with_name("rpc_timeout")
+            .long("rpc-timeout")
+            .value_name("SECONDS")
+            .takes_value(true)
+            .default_value(DEFAULT_RPC_TIMEOUT_SECONDS)
+            .global(true)
+            .hidden(true)
+            .help("Timeout value for RPC requests"),
+    )
+    .arg(
+        Arg::with_name("confirm_transaction_initial_timeout")
+            .long("confirm-timeout")
+            .value_name("SECONDS")
+            .takes_value(true)
+            .default_value(DEFAULT_CONFIRM_TX_TIMEOUT_SECONDS)
+            .global(true)
+            .hidden(true)
+            .help("Timeout value for initial transaction status"),
+    )
+    .subcommand(
+        SubCommand::with_name("config")
+            .about("Solana command-line tool configuration settings")
+            .aliases(&["get", "set"])
+            .setting(AppSettings::SubcommandRequiredElseHelp)
+            .subcommand(
+                SubCommand::with_name("get")
+                    .about("Get current config settings")
+                    .arg(
+                        Arg::with_name("specific_setting")
+                            .index(1)
+                            .value_name("CONFIG_FIELD")
+                            .takes_value(true)
+                            .possible_values(&[
+                                "json_rpc_url",
+                                "websocket_url",
+                                "keypair",
+                                "commitment",
+                            ])
+                            .help("Return a specific config setting"),
+                    ),
+            )
+            .subcommand(
+                SubCommand::with_name("set")
+                    .about("Set a config setting")
+                    .group(
+                        ArgGroup::with_name("config_settings")
+                            .args(&["json_rpc_url", "websocket_url", "keypair", "commitment"])
+                            .multiple(true)
+                            .required(true),
+                    ),
+            )
+            .subcommand(
+                SubCommand::with_name("import-address-labels")
+                    .about("Import a list of address labels")
+                    .arg(
+                        Arg::with_name("filename")
+                            .index(1)
+                            .value_name("FILENAME")
+                            .takes_value(true)
+                            .help("YAML file of address labels"),
+                    ),
+            )
+            .subcommand(
+                SubCommand::with_name("export-address-labels")
+                    .about("Export the current address labels")
+                    .arg(
+                        Arg::with_name("filename")
+                            .index(1)
+                            .value_name("FILENAME")
+                            .takes_value(true)
+                            .help("YAML file to receive the current address labels"),
+                    ),
+            ),
+    )
+    .subcommand(
+        SubCommand::with_name("completion")
+        .about("Generate completion scripts for various shells")
+        .arg(
+            Arg::with_name("shell")
+            .long("shell")
+            .short("s")
+            .takes_value(true)
+            .possible_values(&["bash", "fish", "zsh", "powershell", "elvish"])
+            .default_value("bash")
+        )
+    )
+}
+
+fn base_clap_app<'ab, 'v>(name: &str, about: &'ab str, version: &'v str) -> App<'ab, 'v> {
     App::new(name)
         .about(about)
         .version(version)
@@ -2308,6 +2525,11 @@ pub fn app<'ab, 'v>(name: &str, about: &'ab str, version: &'v str) -> App<'ab, '
         .vote_subcommands()
 }
 
+pub fn get_clap_app<'ab, 'v>(name: &str, about: &'ab str, version: &'v str) -> App<'ab, 'v> {
+    let app = base_clap_app(name, about, version);
+    return finalize_clap_app(app);
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -2417,7 +2639,7 @@ mod tests {
     #[test]
     #[allow(clippy::cognitive_complexity)]
     fn test_cli_parse_command() {
-        let test_commands = app("test", "desc", "version");
+        let test_commands = get_clap_app("test", "desc", "version");
 
         let pubkey = solana_sdk::pubkey::new_rand();
         let pubkey_string = format!("{}", pubkey);
@@ -2954,7 +3176,7 @@ mod tests {
 
     #[test]
     fn test_parse_transfer_subcommand() {
-        let test_commands = app("test", "desc", "version");
+        let test_commands = get_clap_app("test", "desc", "version");
 
         let default_keypair = Keypair::new();
         let default_keypair_file = make_tmp_path("keypair_file");
diff --git a/cli/src/cluster_query.rs b/cli/src/cluster_query.rs
index df5ea834847cb1..27f730d20f904d 100644
--- a/cli/src/cluster_query.rs
+++ b/cli/src/cluster_query.rs
@@ -2143,7 +2143,7 @@ pub fn process_calculate_rent(
 #[cfg(test)]
 mod tests {
     use super::*;
-    use crate::cli::{app, parse_command};
+    use crate::cli::{get_clap_app, parse_command};
     use solana_sdk::signature::{write_keypair, Keypair};
     use std::str::FromStr;
     use tempfile::NamedTempFile;
@@ -2155,7 +2155,7 @@ mod tests {
 
     #[test]
     fn test_parse_command() {
-        let test_commands = app("test", "desc", "version");
+        let test_commands = get_clap_app("test", "desc", "version");
         let default_keypair = Keypair::new();
         let (default_keypair_file, mut tmp_file) = make_tmp_file();
         write_keypair(&default_keypair, tmp_file.as_file_mut()).unwrap();
diff --git a/cli/src/main.rs b/cli/src/main.rs
index a6e91adad43371..7a9c21bce2d66e 100644
--- a/cli/src/main.rs
+++ b/cli/src/main.rs
@@ -1,18 +1,16 @@
 use clap::{
-    crate_description, crate_name, value_t_or_exit, AppSettings, Arg, ArgGroup, ArgMatches,
-    SubCommand,
+    crate_description, crate_name, value_t_or_exit, ArgMatches
 };
 use console::style;
 use solana_clap_utils::{
-    input_validators::{is_url, is_url_or_moniker, normalize_to_url_if_moniker},
-    keypair::{CliSigners, DefaultSigner, SKIP_SEED_PHRASE_VALIDATION_ARG},
-    DisplayError,
+    input_validators::{normalize_to_url_if_moniker},
+    keypair::{CliSigners, DefaultSigner},
+    DisplayError
 };
 use solana_cli::cli::{
-    app, parse_command, process_command, CliCommandInfo, CliConfig, SettingType,
-    DEFAULT_CONFIRM_TX_TIMEOUT_SECONDS, DEFAULT_RPC_TIMEOUT_SECONDS,
+    get_clap_app, parse_command, process_command, CliCommandInfo, CliConfig, SettingType
 };
-use solana_cli_config::{Config, CONFIG_FILE};
+use solana_cli_config::{Config};
 use solana_cli_output::{display::println_name_value, OutputFormat};
 use solana_client::rpc_config::RpcSendTransactionConfig;
 use solana_remote_wallet::remote_wallet::RemoteWalletManager;
@@ -249,179 +247,11 @@ pub fn parse_args<'a>(
 
 fn main() -> Result<(), Box<dyn error::Error>> {
     solana_logger::setup_with_default("off");
-    let matches = app(
+    let matches = get_clap_app(
         crate_name!(),
         crate_description!(),
         solana_version::version!(),
-    )
-    .arg({
-        let arg = Arg::with_name("config_file")
-            .short("C")
-            .long("config")
-            .value_name("FILEPATH")
-            .takes_value(true)
-            .global(true)
-            .help("Configuration file to use");
-        if let Some(ref config_file) = *CONFIG_FILE {
-            arg.default_value(config_file)
-        } else {
-            arg
-        }
-    })
-    .arg(
-        Arg::with_name("json_rpc_url")
-            .short("u")
-            .long("url")
-            .value_name("URL_OR_MONIKER")
-            .takes_value(true)
-            .global(true)
-            .validator(is_url_or_moniker)
-            .help(
-                "URL for Solana's JSON RPC or moniker (or their first letter): \
-                   [mainnet-beta, testnet, devnet, localhost]",
-            ),
-    )
-    .arg(
-        Arg::with_name("websocket_url")
-            .long("ws")
-            .value_name("URL")
-            .takes_value(true)
-            .global(true)
-            .validator(is_url)
-            .help("WebSocket URL for the solana cluster"),
-    )
-    .arg(
-        Arg::with_name("keypair")
-            .short("k")
-            .long("keypair")
-            .value_name("KEYPAIR")
-            .global(true)
-            .takes_value(true)
-            .help("Filepath or URL to a keypair"),
-    )
-    .arg(
-        Arg::with_name("commitment")
-            .long("commitment")
-            .takes_value(true)
-            .possible_values(&[
-                "processed",
-                "confirmed",
-                "finalized",
-                "recent", // Deprecated as of v1.5.5
-                "single", // Deprecated as of v1.5.5
-                "singleGossip", // Deprecated as of v1.5.5
-                "root", // Deprecated as of v1.5.5
-                "max", // Deprecated as of v1.5.5
-            ])
-            .value_name("COMMITMENT_LEVEL")
-            .hide_possible_values(true)
-            .global(true)
-            .help("Return information at the selected commitment level [possible values: processed, confirmed, finalized]"),
-    )
-    .arg(
-        Arg::with_name("verbose")
-            .long("verbose")
-            .short("v")
-            .global(true)
-            .help("Show additional information"),
-    )
-    .arg(
-        Arg::with_name("no_address_labels")
-            .long("no-address-labels")
-            .global(true)
-            .help("Do not use address labels in the output"),
-    )
-    .arg(
-        Arg::with_name("output_format")
-            .long("output")
-            .value_name("FORMAT")
-            .global(true)
-            .takes_value(true)
-            .possible_values(&["json", "json-compact"])
-            .help("Return information in specified output format"),
-    )
-    .arg(
-        Arg::with_name(SKIP_SEED_PHRASE_VALIDATION_ARG.name)
-            .long(SKIP_SEED_PHRASE_VALIDATION_ARG.long)
-            .global(true)
-            .help(SKIP_SEED_PHRASE_VALIDATION_ARG.help),
-    )
-    .arg(
-        Arg::with_name("rpc_timeout")
-            .long("rpc-timeout")
-            .value_name("SECONDS")
-            .takes_value(true)
-            .default_value(DEFAULT_RPC_TIMEOUT_SECONDS)
-            .global(true)
-            .hidden(true)
-            .help("Timeout value for RPC requests"),
-    )
-    .arg(
-        Arg::with_name("confirm_transaction_initial_timeout")
-            .long("confirm-timeout")
-            .value_name("SECONDS")
-            .takes_value(true)
-            .default_value(DEFAULT_CONFIRM_TX_TIMEOUT_SECONDS)
-            .global(true)
-            .hidden(true)
-            .help("Timeout value for initial transaction status"),
-    )
-    .subcommand(
-        SubCommand::with_name("config")
-            .about("Solana command-line tool configuration settings")
-            .aliases(&["get", "set"])
-            .setting(AppSettings::SubcommandRequiredElseHelp)
-            .subcommand(
-                SubCommand::with_name("get")
-                    .about("Get current config settings")
-                    .arg(
-                        Arg::with_name("specific_setting")
-                            .index(1)
-                            .value_name("CONFIG_FIELD")
-                            .takes_value(true)
-                            .possible_values(&[
-                                "json_rpc_url",
-                                "websocket_url",
-                                "keypair",
-                                "commitment",
-                            ])
-                            .help("Return a specific config setting"),
-                    ),
-            )
-            .subcommand(
-                SubCommand::with_name("set")
-                    .about("Set a config setting")
-                    .group(
-                        ArgGroup::with_name("config_settings")
-                            .args(&["json_rpc_url", "websocket_url", "keypair", "commitment"])
-                            .multiple(true)
-                            .required(true),
-                    ),
-            )
-            .subcommand(
-                SubCommand::with_name("import-address-labels")
-                    .about("Import a list of address labels")
-                    .arg(
-                        Arg::with_name("filename")
-                            .index(1)
-                            .value_name("FILENAME")
-                            .takes_value(true)
-                            .help("YAML file of address labels"),
-                    ),
-            )
-            .subcommand(
-                SubCommand::with_name("export-address-labels")
-                    .about("Export the current address labels")
-                    .arg(
-                        Arg::with_name("filename")
-                            .index(1)
-                            .value_name("FILENAME")
-                            .takes_value(true)
-                            .help("YAML file to receive the current address labels"),
-                    ),
-            ),
-    )
-    .get_matches();
+    ).get_matches();
 
     do_main(&matches).map_err(|err| DisplayError::new_as_boxed(err).into())
 }
diff --git a/cli/src/nonce.rs b/cli/src/nonce.rs
index d027f3a227a1da..074d9cd8c5c133 100644
--- a/cli/src/nonce.rs
+++ b/cli/src/nonce.rs
@@ -576,7 +576,7 @@ pub fn process_withdraw_from_nonce_account(
 #[cfg(test)]
 mod tests {
     use super::*;
-    use crate::cli::{app, parse_command};
+    use crate::cli::{get_clap_app, parse_command};
     use solana_sdk::{
         account::Account,
         account_utils::StateMut,
@@ -596,7 +596,7 @@ mod tests {
 
     #[test]
     fn test_parse_command() {
-        let test_commands = app("test", "desc", "version");
+        let test_commands = get_clap_app("test", "desc", "version");
         let default_keypair = Keypair::new();
         let (default_keypair_file, mut tmp_file) = make_tmp_file();
         write_keypair(&default_keypair, tmp_file.as_file_mut()).unwrap();
diff --git a/cli/src/program.rs b/cli/src/program.rs
index 8e5f1b77bcaf9c..c7e0610f797416 100644
--- a/cli/src/program.rs
+++ b/cli/src/program.rs
@@ -2118,7 +2118,7 @@ fn send_and_confirm_transactions_with_spinner<T: Signers>(
 #[cfg(test)]
 mod tests {
     use super::*;
-    use crate::cli::{app, parse_command, process_command};
+    use crate::cli::{get_clap_app, parse_command, process_command};
     use serde_json::Value;
     use solana_cli_output::OutputFormat;
     use solana_sdk::signature::write_keypair_file;
@@ -2140,7 +2140,7 @@ mod tests {
     #[test]
     #[allow(clippy::cognitive_complexity)]
     fn test_cli_parse_deploy() {
-        let test_commands = app("test", "desc", "version");
+        let test_commands = get_clap_app("test", "desc", "version");
 
         let default_keypair = Keypair::new();
         let keypair_file = make_tmp_path("keypair_file");
@@ -2348,7 +2348,7 @@ mod tests {
     #[test]
     #[allow(clippy::cognitive_complexity)]
     fn test_cli_parse_write_buffer() {
-        let test_commands = app("test", "desc", "version");
+        let test_commands = get_clap_app("test", "desc", "version");
 
         let default_keypair = Keypair::new();
         let keypair_file = make_tmp_path("keypair_file");
@@ -2496,7 +2496,7 @@ mod tests {
     #[test]
     #[allow(clippy::cognitive_complexity)]
     fn test_cli_parse_set_upgrade_authority() {
-        let test_commands = app("test", "desc", "version");
+        let test_commands = get_clap_app("test", "desc", "version");
 
         let default_keypair = Keypair::new();
         let keypair_file = make_tmp_path("keypair_file");
@@ -2604,7 +2604,7 @@ mod tests {
     #[test]
     #[allow(clippy::cognitive_complexity)]
     fn test_cli_parse_set_buffer_authority() {
-        let test_commands = app("test", "desc", "version");
+        let test_commands = get_clap_app("test", "desc", "version");
 
         let default_keypair = Keypair::new();
         let keypair_file = make_tmp_path("keypair_file");
@@ -2661,7 +2661,7 @@ mod tests {
     #[test]
     #[allow(clippy::cognitive_complexity)]
     fn test_cli_parse_show() {
-        let test_commands = app("test", "desc", "version");
+        let test_commands = get_clap_app("test", "desc", "version");
 
         let default_keypair = Keypair::new();
         let keypair_file = make_tmp_path("keypair_file");
@@ -2760,7 +2760,7 @@ mod tests {
     #[test]
     #[allow(clippy::cognitive_complexity)]
     fn test_cli_parse_close() {
-        let test_commands = app("test", "desc", "version");
+        let test_commands = get_clap_app("test", "desc", "version");
 
         let default_keypair = Keypair::new();
         let keypair_file = make_tmp_path("keypair_file");
diff --git a/cli/src/stake.rs b/cli/src/stake.rs
index e28597e87609f5..77021145530dda 100644
--- a/cli/src/stake.rs
+++ b/cli/src/stake.rs
@@ -2358,7 +2358,7 @@ pub fn is_stake_program_v2_enabled(
 #[cfg(test)]
 mod tests {
     use super::*;
-    use crate::cli::{app, parse_command};
+    use crate::cli::{get_clap_app, parse_command};
     use solana_client::blockhash_query;
     use solana_sdk::{
         hash::Hash,
@@ -2376,7 +2376,7 @@ mod tests {
     #[test]
     #[allow(clippy::cognitive_complexity)]
     fn test_parse_command() {
-        let test_commands = app("test", "desc", "version");
+        let test_commands = get_clap_app("test", "desc", "version");
         let default_keypair = Keypair::new();
         let (default_keypair_file, mut tmp_file) = make_tmp_file();
         write_keypair(&default_keypair, tmp_file.as_file_mut()).unwrap();
diff --git a/cli/src/validator_info.rs b/cli/src/validator_info.rs
index 6ac5f239b95a4d..03a4df9d284fea 100644
--- a/cli/src/validator_info.rs
+++ b/cli/src/validator_info.rs
@@ -408,7 +408,7 @@ pub fn process_get_validator_info(
 #[cfg(test)]
 mod tests {
     use super::*;
-    use crate::cli::app;
+    use crate::cli::get_clap_app;
     use bincode::{serialize, serialized_size};
     use serde_json::json;
 
@@ -432,7 +432,7 @@ mod tests {
 
     #[test]
     fn test_parse_args() {
-        let matches = app("test", "desc", "version").get_matches_from(vec![
+        let matches = get_clap_app("test", "desc", "version").get_matches_from(vec![
             "test",
             "validator-info",
             "publish",
diff --git a/cli/src/vote.rs b/cli/src/vote.rs
index ce27c55cf11cec..56039f697b709c 100644
--- a/cli/src/vote.rs
+++ b/cli/src/vote.rs
@@ -880,7 +880,7 @@ pub fn process_withdraw_from_vote_account(
 #[cfg(test)]
 mod tests {
     use super::*;
-    use crate::cli::{app, parse_command};
+    use crate::cli::{get_clap_app, parse_command};
     use solana_sdk::signature::{read_keypair_file, write_keypair, Keypair, Signer};
     use tempfile::NamedTempFile;
 
@@ -891,7 +891,7 @@ mod tests {
 
     #[test]
     fn test_parse_command() {
-        let test_commands = app("test", "desc", "version");
+        let test_commands = get_clap_app("test", "desc", "version");
         let keypair = Keypair::new();
         let pubkey = keypair.pubkey();
         let pubkey_string = pubkey.to_string();