Improved live logging

.SRCINFO

@@ -0,0 +1,10 @@
+pkgbase = rexec
+	pkgdesc = Parallel SSH executor
+	pkgver = 1.0.6
+	pkgrel = 1
+	url = https://github.com/house-of-vanity/rexec
+	arch = x86_64
+	license = WTFPL
+	makedepends = cargo
+
+pkgname = rexec

.github/workflows/release.yml

@@ -1,80 +1,140 @@
 name: Rust static build and publish
+
 on:
   push:
     tags:
-    - '*'
+      - 'v*.*.*'
+
 env:
   CARGO_TERM_COLOR: always
-  BUILD_TARGET: x86_64-unknown-linux-musl
   BINARY_NAME: rexec
+
 jobs:
   build:
     name: Build static binary
-    runs-on: ubuntu-latest
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: [ubuntu-latest, windows-latest, macos-latest]
+        include:
+          - os: ubuntu-latest
+            build_target: x86_64-unknown-linux-musl
+            platform_name: linux-amd64
+          - os: windows-latest
+            build_target: x86_64-pc-windows-msvc
+            platform_name: windows-amd64
+          - os: macos-latest
+            build_target: aarch64-apple-darwin
+            platform_name: macos-arm64
     permissions:
       contents: write
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
+      
+      - name: Cache Cargo registry
+        uses: actions/cache@v4
+        with:
+          path: ~/.cargo/registry
+          key: ${{ runner.os }}-cargo-registry-${{ hashFiles('**/Cargo.lock') }}
+          restore-keys: |
+            ${{ runner.os }}-cargo-registry-
+      
+      - name: Cache Cargo index
+        uses: actions/cache@v4
+        with:
+          path: ~/.cargo/git
+          key: ${{ runner.os }}-cargo-index-${{ hashFiles('**/Cargo.lock') }}
+          restore-keys: |
+            ${{ runner.os }}-cargo-index-
+      
+      - name: Cache Cargo build
+        uses: actions/cache@v4
+        with:
+          path: target
+          key: ${{ runner.os }}-cargo-build-${{ hashFiles('**/Cargo.lock') }}
+          restore-keys: |
+            ${{ runner.os }}-cargo-build-
+
       - uses: dtolnay/rust-toolchain@stable
+      
       - uses: mbrobbel/rustfmt-check@master
         with:
           token: ${{ secrets.GITHUB_TOKEN }}
-      - name: Build-musl
+          
+      - name: Install rust targets
+        run: rustup target add ${{ matrix.build_target }}
+        
+      - name: Build Linux MUSL
+        if: matrix.os == 'ubuntu-latest'
         uses: gmiam/rust-musl-action@master
         with:
-          args: cargo build --target $BUILD_TARGET --release
+          args: cargo build --target ${{ matrix.build_target }} --release
-      - uses: actions/upload-artifact@v2
-        name: Upload artifact
-        with:
-          name: ${{ env.BINARY_NAME }}_x86_64-linux-musl
-          path: target/x86_64-unknown-linux-musl/release/${{ env.BINARY_NAME }}
           
-#  build_arch:
+      - name: Build MacOS
-#    name: Arch Linux package
+        if: matrix.os == 'macos-latest'
-#    runs-on: ubuntu-latest
+        run: cargo build --target ${{ matrix.build_target }} --release
-#    permissions:
+          
-#      contents: write
+      - name: Build Windows
-#    steps:
+        if: matrix.os == 'windows-latest'
-#    - uses: actions/checkout@v3
+        run: cargo build --target ${{ matrix.build_target }} --release
-#    - name: Install latest nightly
+          
-#      uses: actions-rs/toolchain@v1
+      - name: Upload artifact
-#      with:
+        uses: actions/upload-artifact@v4
-#        toolchain: stable
+        with:
-#        override: true
+          name: ${{ env.BINARY_NAME }}_${{ matrix.platform_name }}
-#        target: x86_64-unknown-linux-musl
+          path: target/${{ matrix.build_target }}/release/${{ env.BINARY_NAME }}*
-#        components: rustfmt
-#    - name: Install cargo-aur
-#      run: cargo install cargo-aur
-#    - name: Build PKGBUILD
-#      uses: actions-rs/cargo@v1
-#      with:
-#        command: aur
-#    - uses: actions/upload-artifact@v2
-#      name: Upload artifact PKGBUILD
-#      with:
-#          path: PKGBUILD
-#          name: PKGBUILD
 
   release:
-    name: Release binary
+    name: Create Release Page
-    needs: ["build"]
+    needs: build
     runs-on: ubuntu-latest
+    outputs:
+      upload_url: ${{ steps.create_release.outputs.upload_url }}
     permissions:
       contents: write
     steps:
-    - uses: actions/download-artifact@master
+      - uses: actions/checkout@v4
-      id: download_binary
+      - name: Get version
-      with:
+        run: echo "VERSION=$(grep -P '^version = \"\d+\.\d+\.\d+\"' Cargo.toml | awk -F '\"' '{print $2}')" >> $GITHUB_ENV
-        name: ${{ env.BINARY_NAME }}_x86_64-linux-musl
+      - name: Show version
-        path: ${{ env.BINARY_NAME }}_x86_64-linux-musl
+        run: echo ${{ env.VERSION }}
-#    - uses: actions/download-artifact@master
+      - uses: ncipollo/release-action@v1
-#      id: download_pkgbuild
+        id: create_release
-#      with:
+        env:
-#        name: PKGBUILD
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-#        path: PKGBUILD
+        with:
-    - uses: ncipollo/release-action@v1
+          allowUpdates: true
-      name: Update release page
+          body: "Release rexec ${{ env.VERSION }}. Static build for Linux (x86_64), Windows (x86_64) и MacOS (arm64)."
-      with:
+
-        artifacts: "${{ steps.download_binary.outputs.download-path }}/*"
+  upload:
-        allowUpdates: true
+    name: Upload Release Assets
-        body: Static build for x86_64-linux using MUSL
+    needs: release
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: [ubuntu-latest, windows-latest, macos-latest]
+        include:
+          - os: ubuntu-latest
+            platform_name: linux-amd64
+          - os: windows-latest
+            platform_name: windows-amd64
+          - os: macos-latest
+            platform_name: macos-arm64
+    steps:
+      - uses: actions/checkout@v4
+      
+      - uses: actions/download-artifact@v4
+        name: Download ${{ matrix.platform_name }} artifact
+        with:
+          name: ${{ env.BINARY_NAME }}_${{ matrix.platform_name }}
+          path: ${{ env.BINARY_NAME }}_${{ matrix.platform_name }}
+          
+      - name: Upload Release Asset
+        uses: actions/upload-release-asset@v1
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        with:
+          upload_url: ${{ needs.release.outputs.upload_url }}
+          asset_path: ${{ env.BINARY_NAME }}_${{ matrix.platform_name }}/${{ env.BINARY_NAME }}${{ matrix.platform_name == 'windows-amd64' && '.exe' || '' }}
+          asset_name: ${{ env.BINARY_NAME }}_${{ matrix.platform_name }}${{ matrix.platform_name == 'windows-amd64' && '.exe' || '' }}
+          asset_content_type: application/octet-stream

.gitignore

@@ -1 +1,7 @@
 target
+pkg
+*zst
+.rustup
+.cargo
+.viminfo
+.bash_history

CHANGELOG.md

@@ -6,6 +6,26 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 
+
+## [1.1.0] - 2023-09-13
+
+### Improved
+
+- Logging. Fix bugs 
+
+
+## [1.0.7] - 2023-08-31
+
+### Changed
+
+- Ci 
+
+## [1.0.4] - 2023-08-14
+
+### Changed
+
+- Expansion host strings.
+
 ## [1.0.1] - 2023-06-20
 
 ### Changed

Cargo.toml

@@ -1,6 +1,7 @@
 [package]
 name = "rexec"
-version = "1.0.2"
+version = "1.5.1"
+readme = "https://github.com/house-of-vanity/rexec#readme"
 edition = "2021"
 description = "Parallel SSH executor"
 repository = "https://github.com/house-of-vanity/rexec"
@@ -12,15 +13,16 @@ authors = ["AB <gh@hexor.ru>"]
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-dns-lookup = "2.0.2"
+dns-lookup = "2"
-log = "0.4.0"
+rayon = "1.10"
-env_logger = "0.10.0"
+log = "0.4"
-massh = "0.6.3"
+env_logger = "0.11"
-whoami = "1.4.0"
+whoami = "1"
-lazy-st = "0.2.2"
+lazy-st = "1"
 regex = "1"
-clap = { version = "4.3.4", features = ["derive"] }
+clap = { version = "4.5", features = ["derive"] }
-colored = "2.0.0"
+colored = "3"
-dialoguer = "0.10.4"
+itertools = "0.14"
-itertools = "0.10.5"
 brace-expand = "0.1.0"
+question = "0.2.2"
+lazy_static = "1.5.0"

PKGBUILD

@@ -0,0 +1,14 @@
+# Maintainer: AB <gh@hexor.ru>
+pkgname=rexec
+pkgver=some_ver
+pkgrel=1
+pkgdesc="Parallel SSH executor"
+url="https://github.com/house-of-vanity/rexec"
+license=("WTFPL")
+arch=("x86_64")
+
+package() {
+  install -Dm755 "$startdir/target/x86_64-unknown-linux-musl/release/rexec" "$pkgdir/usr/bin/rexec"
+}
+
+

README.md

@@ -1,14 +1,20 @@
 # rexec
-Parallel SSH executor in Rust. It can read servers from `~/.ssh/known_hosts`
+**Parallel SSH executor** in Rust with static binary. It can read servers from `~/.ssh/known_hosts`
-
-or even expand servers from bash expanshion line `cassandra.{prod,dev}.example.com`
 
+or even expand servers from bash expanshion line `cassandra-[1:5].{prod,dev}.example.com`
 
 [![Rust-static-build](https://github.com/house-of-vanity/rexec/actions/workflows/release.yml/badge.svg)](https://github.com/house-of-vanity/rexec/actions/workflows/release.yml)
+---
 
-
+## Usage
 ```shell                                                    
-[ab@test]$ ./rexec -k admin-gce-sc.* --help
+            _|_|_|_|   _|      _|   _|_|_|_|     _|_|_|  
+ _|  _|_|   _|           _|  _|     _|         _|        
+ _|_|       _|_|_|         _|       _|_|_|     _|        
+ _|         _|           _|  _|     _|         _|        
+ _|         _|_|_|_|   _|      _|   _|_|_|_|     _|_|_|  
+                                                        
+
 Parallel SSH executor in Rust
 
 Usage: rexec [OPTIONS] --expression <EXPRESSION> --command <COMMAND>
@@ -24,39 +30,33 @@ Options:
   -h, --help                     Print help
   -V, --version                  Print version
 ```
+---
 
+![image](https://github.com/house-of-vanity/rexec/assets/4666566/4c52915d-2bc1-46b9-9833-b0d7c0527f2d)
+
+
+## Examples
 ```shell
-[ab@test debug]$ ./rexec -u ab -k -c uptime -e admin.* -f
+$ rexec -f \
+    -e 'cassandra-gce-or-[1:2]' \
+    -u ab \
+    -c 'uname -r; date'
+[INFO ] Using string expansion to build server list.
 [INFO ] Matched hosts:
-[INFO ] admin-gce-sc-1.lca-prod.** [35.211.27.195]
+[INFO ] cassandra-gce-or-1.prod.example.com [2.22.123.79]
-[INFO ] admin-gce-sc-1.mmk-prod.** [35.211.79.202]
+[INFO ] cassandra-gce-or-2.prod.example.com [2.22.123.158]
-[ERROR] admin-gce-sc-1.led-prod.** couldn't be resolved.
+Continue on following 2 servers? y
-[INFO ] admin-gce-sc-1.msq-dev.** [35.211.0.24]
+[INFO ] Run command on 2 servers.
-[ERROR] admin-gce-sc-1.hui-dev.** couldn't be resolved.
 
-[INFO ] Run command on 3 servers.
+cassandra-gce-or-1.prod.example.com
+Exit code [0] / stdout 45 bytes / stderr 0 bytes
+STDOUT
+║ 5.15.0-1040-gcp
+║ Thu Sep  7 13:44:40 UTC 2023
 
-
+cassandra-gce-or-2.prod.example.com
-[INFO ] admin.gnb-prod.**
+Exit code [0] / stdout 45 bytes / stderr 0 bytes
-Code 0 
+STDOUT
-STDOUT:                                                    
+║ 5.15.0-1040-gcp
- 23:31:21 up 294 days, 14:14,  0 users,  load average: 0.53, 0.64, 0.52
+║ Thu Sep  7 13:44:40 UTC 2023
-
-STDERR:
-                                                                                                                       
-[INFO ] admin.abe-prod.**
-Code 0 
-STDOUT:                                                    
- 23:31:22 up 154 days,  9:24,  0 users,  load average: 0.31, 0.25, 0.18
-                                                           
-STDERR:
-
-[INFO ] admin-gce-be-1.toy-prod.**
-Code 0                                                     
-STDOUT:
- 23:31:22 up 98 days,  6:20,  0 users,  load average: 0.88, 0.74, 0.80
-                             
-STDERR:
-no server running on /tmp/tmux-1019/default                                                                            
-open terminal failed: not a terminal
 ```

src/main.rs

@@ -1,42 +1,64 @@
-#[macro_use]
 extern crate log;
 
-use std::collections::HashMap;
 use std::fs::read_to_string;
 use std::hash::Hash;
+use std::io::{BufRead, BufReader};
 use std::net::IpAddr;
-use std::process;
+use std::process::{self, Command, Stdio};
+use std::sync::{Arc, Mutex};
+use std::thread;
 
 use clap::Parser;
 use colored::*;
-use dialoguer::Confirm;
 use dns_lookup::lookup_host;
 use env_logger::Env;
 use itertools::Itertools;
-use log::{error, info};
+use lazy_static::lazy_static;
-use massh::{MasshClient, MasshConfig, MasshHostConfig, SshAuth};
+use log::{error, info, warn};
+use question::{Answer, Question};
+use rayon::prelude::*;
 use regex::Regex;
 
+// Global state to track the currently open block
+lazy_static! {
+    static ref CURRENT_BLOCK: Arc<Mutex<Option<String>>> = Arc::new(Mutex::new(None));
+}
 
-// Define args
+// Define command-line arguments using the clap library
 #[derive(Parser, Debug)]
 #[command(author = "AB ab@hexor.ru", version, about = "Parallel SSH executor in Rust", long_about = None)]
 struct Args {
-    #[arg(short, long, default_value_t = whoami::username())]
+    /// Username for SSH connections (defaults to current system user)
+    #[arg(short = 'u', short_alias = 'l', long, default_value_t = whoami::username())]
     username: String,
 
-    #[arg(short, long, help = "Use known_hosts to build servers list")]
+    /// Flag to use known_hosts file for server discovery instead of pattern expansion
+    #[arg(
+        short,
+        long,
+        help = "Use known_hosts to build servers list instead of string expansion."
+    )]
     known_hosts: bool,
 
-    #[arg(short, long, help = "Expression to build server list. List and range expansion available. Example: 'web-[1:12]-io-{prod,dev}'")]
+    /// Server name patterns with expansion syntax
-    expression: String,
+    /// Examples: 'web-[1:12]-io-{prod,dev}' expands to multiple servers
+    #[arg(
+        short,
+        long,
+        num_args = 1..,
+        help = "Expression to build server list. List and range expansion are supported. Example: 'web-[1:12]-io-{prod,dev}'"
+    )]
+    expression: Vec<String>,
 
+    /// Command to execute on each server
     #[arg(short, long, help = "Command to execute on servers")]
     command: String,
 
+    /// Display only exit codes without command output
     #[arg(long, default_value_t = false, help = "Show exit code ONLY")]
     code: bool,
 
+    /// Skip confirmation prompt before executing commands
     #[arg(
         short = 'f',
         long,
@@ -45,21 +67,104 @@ struct Args {
     )]
     noconfirm: bool,
 
+    /// Maximum number of parallel SSH connections
     #[arg(short, long, default_value_t = 100)]
     parallel: i32,
 }
 
-// Represent line from known_hosts file
+/// Host representation for both known_hosts entries and expanded patterns
 #[derive(Debug, Default, Clone, PartialEq, Eq, Hash)]
 struct Host {
+    /// Hostname or IP address as a string
     name: String,
+    /// Resolved IP address (if available)
     ip: Option<IpAddr>,
 }
 
-// Read known_hosts file
+/// Find common domain suffix across all hostnames to simplify output display
+///
+/// This function analyzes all hostnames to identify a common domain suffix
+/// which can be shortened during display to improve readability.
+///
+/// # Arguments
+/// * `hostnames` - A slice of strings containing all server hostnames
+///
+/// # Returns
+/// * `Option<String>` - The common suffix if found, or None
+fn find_common_suffix(hostnames: &[String]) -> Option<String> {
+    if hostnames.is_empty() {
+        return None;
+    }
+
+    // Don't truncate if only one host
+    if hostnames.len() == 1 {
+        return None;
+    }
+
+    let first = &hostnames[0];
+
+    // Start with assumption that the entire first hostname is the common suffix
+    let mut common = first.clone();
+
+    // Iterate through remaining hostnames, reducing the common part
+    for hostname in hostnames.iter().skip(1) {
+        // Exit early if no common part remains
+        if common.is_empty() {
+            return None;
+        }
+
+        // Find common suffix with current hostname
+        let mut new_common = String::new();
+
+        // Search for common suffix by comparing characters from right to left
+        let mut common_chars = common.chars().rev();
+        let mut hostname_chars = hostname.chars().rev();
+
+        loop {
+            match (common_chars.next(), hostname_chars.next()) {
+                (Some(c1), Some(c2)) if c1 == c2 => new_common.insert(0, c1),
+                _ => break,
+            }
+        }
+
+        common = new_common;
+    }
+
+    // Ensure the common part is a valid domain suffix (starts with a dot)
+    if common.is_empty() || !common.starts_with('.') {
+        return None;
+    }
+
+    // Return the identified common suffix
+    Some(common)
+}
+
+/// Shorten hostname by removing the common suffix and replacing with an asterisk
+///
+/// # Arguments
+/// * `hostname` - The original hostname
+/// * `common_suffix` - Optional common suffix to remove
+///
+/// # Returns
+/// * `String` - Shortened hostname or original if no common suffix
+fn shorten_hostname(hostname: &str, common_suffix: &Option<String>) -> String {
+    match common_suffix {
+        Some(suffix) if hostname.ends_with(suffix) => {
+            let short_name = hostname[..hostname.len() - suffix.len()].to_string();
+            format!("{}{}", short_name, "*")
+        }
+        _ => hostname.to_string(),
+    }
+}
+
+/// Read and parse the SSH known_hosts file to extract server names
+///
+/// # Returns
+/// * `Vec<Host>` - List of hosts found in the known_hosts file
 fn read_known_hosts() -> Vec<Host> {
     let mut result: Vec<Host> = Vec::new();
 
+    // Read known_hosts file from the user's home directory
     for line in read_to_string(format!("/home/{}/.ssh/known_hosts", whoami::username()))
         .unwrap()
         .lines()
@@ -74,51 +179,91 @@ fn read_known_hosts() -> Vec<Host> {
     result
 }
 
-fn expand_string(string: String) -> Vec<Host> {
+/// Expand a numeric range in the format [start:end] to a list of strings
-    let mut result: Vec<String> = Vec::new();
+///
-    let mut _result: Vec<String> = Vec::new();
+/// # Arguments
+/// * `start` - Starting number (inclusive)
+/// * `end` - Ending number (inclusive)
+///
+/// # Returns
+/// * `Vec<String>` - List of numbers as strings
+fn expand_range(start: i32, end: i32) -> Vec<String> {
+    (start..=end).map(|i| i.to_string()).collect()
+}
+
+/// Expand a comma-separated list in the format {item1,item2,item3} to a list of strings
+///
+/// # Arguments
+/// * `list` - Comma-separated string to expand
+///
+/// # Returns
+/// * `Vec<String>` - List of expanded items
+fn expand_list(list: &str) -> Vec<String> {
+    list.split(',').map(|s| s.to_string()).collect()
+}
+
+/// Expand a server pattern string with range and list notation into individual hostnames
+///
+/// Supports two expansion types:
+/// - Range expansion: server-[1:5] → server-1, server-2, server-3, server-4, server-5
+/// - List expansion: server-{prod,dev} → server-prod, server-dev
+///
+/// # Arguments
+/// * `s` - Pattern string to expand
+///
+/// # Returns
+/// * `Vec<Host>` - List of expanded Host objects
+fn expand_string(s: &str) -> Vec<Host> {
     let mut hosts: Vec<Host> = Vec::new();
+    let mut result = vec![s.to_string()];
 
-    if let Some(open_bracket_index) = string.find('[') {
+    // First expand all range expressions [start:end]
-        if let Some(close_bracket_index) = string.find(']') {
+    while let Some(r) = result.iter().find(|s| s.contains('[')) {
-            let prefix = &string[..open_bracket_index];
+        let r = r.clone();
-            let range = &string[open_bracket_index + 1..close_bracket_index];
+        let start = r.find('[').unwrap();
-            let postfix = &string[close_bracket_index + 1..];
+        let end = match r[start..].find(']') {
-
+            None => {
-            let parts: Vec<&str> = range.split(':').collect();
+                error!("Error parsing host expression. Wrong range expansion '[a:b]'");
-
+                process::exit(1);
-            if parts.len() == 2 {
-                if let Ok(start) = parts[0].parse::<u32>() {
-                    if let Ok(end) = parts[1].parse::<u32>() {
-                        for num in start..=end {
-                            _result.push(format!("{}{}{}", prefix, num, postfix));
-                        }
-                    }
-                }
             }
-        }
+            Some(s) => s + start,
-    } else {
+        };
-        _result.push(String::from(string));
+        let colon = match r[start..end].find(':') {
-    }
+            None => {
-
+                error!("Error parsing host expression. Missing colon in range expansion '[a:b]'");
-    for string in _result {
+                process::exit(1);
-        if let Some(open_brace_index) = string.find('{') {
-            if let Some(close_brace_index) = string.find('}') {
-                let prefix = &string[..open_brace_index];
-                let list = &string[open_brace_index + 1..close_brace_index];
-                let postfix = &string[close_brace_index + 1..];
-
-                let items: Vec<&str> = list.split(',').collect();
-
-                for item in items {
-                    result.push(format!("{}{}{}", prefix, item, postfix));
-                }
             }
-        } else {
+            Some(c) => c + start,
-            result.push(String::from(string));
+        };
+        let low = r[start + 1..colon].parse::<i32>().unwrap();
+        let high = r[colon + 1..end].parse::<i32>().unwrap();
+        result.retain(|s| s != &r);
+        for val in expand_range(low, high) {
+            let new_str = format!("{}{}{}", &r[..start], val, &r[end + 1..]);
+            result.push(new_str);
         }
     }
 
+    // Then expand all list expressions {item1,item2}
+    while let Some(r) = result.iter().find(|s| s.contains('{')) {
+        let r = r.clone();
+        let start = r.find('{').unwrap();
+        let end = match r.find('}') {
+            None => {
+                error!("Error parsing host expression. Wrong range expansion '{{one,two}}'");
+                process::exit(1);
+            }
+            Some(s) => s,
+        };
+        let list = &r[start + 1..end];
+        result.retain(|s| s != &r);
+        for val in expand_list(list) {
+            let new_str = format!("{}{}{}", &r[..start], val, &r[end + 1..]);
+            result.push(new_str);
+        }
+    }
+
+    // Convert all expanded strings to Host objects
     for hostname in result {
         hosts.push(Host {
             name: hostname.to_string(),
@@ -128,121 +273,354 @@ fn expand_string(string: String) -> Vec<Host> {
     hosts
 }
 
+/// Execute a command on a single host using the system SSH client
+///
+/// This function runs an SSH command using the system's SSH client,
+/// capturing and displaying output in real-time with proper formatting.
+///
+/// # Arguments
+/// * `hostname` - Target server hostname
+/// * `username` - SSH username
+/// * `command` - Command to execute
+/// * `common_suffix` - Optional common suffix for hostname display formatting
+/// * `code_only` - Whether to display only exit codes
+///
+/// # Returns
+/// * `Result<i32, String>` - Exit code on success or error message
+fn execute_ssh_command(
+    hostname: &str,
+    username: &str,
+    command: &str,
+    common_suffix: &Option<String>,
+    code_only: bool,
+) -> Result<i32, String> {
+    let display_name = shorten_hostname(hostname, common_suffix);
+
+    // Build the SSH command with appropriate options
+    let mut ssh_cmd = Command::new("ssh");
+    ssh_cmd
+        .arg("-o")
+        .arg("StrictHostKeyChecking=no")
+        .arg("-o")
+        .arg("BatchMode=yes")
+        .arg(format!("{}@{}", username, hostname))
+        .arg(command)
+        .stdout(Stdio::piped())
+        .stderr(Stdio::piped());
+
+    // Execute the command
+    let mut child = match ssh_cmd.spawn() {
+        Ok(child) => child,
+        Err(e) => return Err(format!("Failed to start SSH process: {}", e)),
+    };
+
+    // Function to handle output lines with proper block management
+    let handle_output = |line: String, display_name: &str, code_only: bool, is_stderr: bool| {
+        if !code_only {
+            let mut current_block = CURRENT_BLOCK.lock().unwrap();
+
+            // Check if we need to close the previous block and open a new one
+            match current_block.as_ref() {
+                Some(open_host) if open_host != display_name => {
+                    // Close the previous block
+                    println!("└ {} ┘", open_host.yellow());
+                    // Open new block
+                    println!("┌ {} ┐", display_name.yellow());
+                    *current_block = Some(display_name.to_string());
+                }
+                None => {
+                    // Open new block
+                    println!("┌ {} ┐", display_name.yellow());
+                    *current_block = Some(display_name.to_string());
+                }
+                Some(_) => {
+                    // Same host, continue with current block
+                }
+            }
+
+            // Print the log line with colored separator based on stream type
+            let separator = if is_stderr {
+                "│".red()
+            } else {
+                "│".green()
+            };
+            println!(
+                "{} {} {} {}",
+                separator,
+                display_name.yellow(),
+                separator,
+                line
+            );
+        }
+    };
+
+    // Capture and display stdout in real-time using a dedicated thread
+    let stdout = child.stdout.take().unwrap();
+    let display_name_stdout = display_name.clone();
+    let code_only_stdout = code_only;
+    let stdout_thread = thread::spawn(move || {
+        let reader = BufReader::new(stdout);
+
+        for line in reader.lines() {
+            match line {
+                Ok(line) => {
+                    handle_output(line, &display_name_stdout, code_only_stdout, false);
+                    // false = stdout
+                }
+                Err(_) => break,
+            }
+        }
+    });
+
+    // Capture and display stderr in real-time using a dedicated thread
+    let stderr = child.stderr.take().unwrap();
+    let display_name_stderr = display_name.clone();
+    let code_only_stderr = code_only;
+    let stderr_thread = thread::spawn(move || {
+        let reader = BufReader::new(stderr);
+
+        for line in reader.lines() {
+            match line {
+                Ok(line) => {
+                    handle_output(line, &display_name_stderr, code_only_stderr, true);
+                    // true = stderr
+                }
+                Err(_) => break,
+            }
+        }
+    });
+
+    // Wait for command to complete
+    let status = match child.wait() {
+        Ok(status) => status,
+        Err(e) => return Err(format!("Failed to wait for SSH process: {}", e)),
+    };
+
+    // Wait for stdout and stderr threads to complete
+    stdout_thread.join().unwrap();
+    stderr_thread.join().unwrap();
+
+    // Close the block if this host was the last one to output
+    if !code_only {
+        let mut current_block = CURRENT_BLOCK.lock().unwrap();
+        if let Some(open_host) = current_block.as_ref() {
+            if open_host == &display_name {
+                println!("└ {} ┘", display_name.yellow());
+                *current_block = None;
+            }
+        }
+    }
+
+    // Format exit code with color (green for success, red for failure)
+    let exit_code = status.code().unwrap_or(-1);
+    let code_string = if exit_code == 0 {
+        format!("{}", exit_code.to_string().green())
+    } else {
+        format!("{}", exit_code.to_string().red())
+    };
+
+    // For code-only mode, just show hostname and exit code
+    if code_only {
+        println!("{}: [{}]", display_name.yellow(), code_string);
+    }
+
+    Ok(exit_code)
+}
+
+/// Main entry point for the application
 fn main() {
+    // Initialize logging with minimal formatting (no timestamp, no target)
     env_logger::Builder::from_env(Env::default().default_filter_or("info"))
         .format_timestamp(None)
         .format_target(false)
         .init();
+
+    // Parse command-line arguments
     let args = Args::parse();
 
+    // Build the list of target hosts based on user selection method
     let hosts = if args.known_hosts {
+        // Use regex pattern matching against known_hosts file
         info!("Using ~/.ssh/known_hosts to build server list.");
         let known_hosts = read_known_hosts();
-        // Build regex
+        let mut all_hosts = Vec::new();
-        let re = match Regex::new(&args.expression) {
+        for expression in args.expression.iter() {
-            Ok(result) => result,
+            let re = match Regex::new(expression) {
-            Err(e) => {
+                Ok(result) => result,
-                error!("Error parsing regex. {}", e);
-                process::exit(1);
-            }
-        };
-        // match hostnames from known_hosts to regex
-        known_hosts
-            .into_iter()
-            .filter(|r| re.is_match(&r.name.clone()))
-            .collect()
-    } else {
-        info!("Using string expansion to build server list.");
-        expand_string(args.expression)
-    };
-
-    // Dedup hosts from known_hosts file
-    let matched_hosts: Vec<_> = hosts.into_iter().unique().collect();
-
-    // Build MasshHostConfig hostnames list
-    let mut massh_hosts: Vec<MasshHostConfig> = vec![];
-    let mut hosts_and_ips: HashMap<IpAddr, String> = HashMap::new();
-    info!("Matched hosts:");
-    for host in matched_hosts.iter() {
-        let ip = match lookup_host(&host.name) {
-            Ok(ip) => ip[0],
-            Err(_) => {
-                error!("{} couldn't be resolved.", &host.name.red());
-                continue;
-            }
-        };
-        info!("{} [{}]", &host.name, ip);
-        hosts_and_ips.insert(ip, host.name.clone());
-        massh_hosts.push(MasshHostConfig {
-            addr: ip,
-            auth: None,
-            port: None,
-            user: None,
-        })
-    }
-    // Build MasshConfig using massh_hosts vector
-    let config = MasshConfig {
-        default_auth: SshAuth::Agent,
-        default_port: 22,
-        default_user: args.username,
-        threads: args.parallel as u64,
-        timeout: 0,
-        hosts: massh_hosts,
-    };
-    let massh = MasshClient::from(&config);
-
-    // Ask for confirmation
-    if args.noconfirm == true
-        || Confirm::new()
-            .with_prompt(format!(
-                "Continue on following {} servers?",
-                &config.hosts.len()
-            ))
-            .interact()
-            .unwrap()
-    {
-        info!("\n");
-        info!("Run command on {} servers.", &config.hosts.len());
-        info!("\n");
-
-        // Run a command on all the configured hosts.
-        // Receive the result of the command for each host and print its output.
-        let rx = massh.execute(args.command);
-
-        while let Ok((host, result)) = rx.recv() {
-            let ip: String = host.split('@').collect::<Vec<_>>()[1]
-                .split(':')
-                .collect::<Vec<_>>()[0]
-                .to_string();
-            let ip = ip.parse::<IpAddr>().unwrap();
-            info!(
-                "{}",
-                hosts_and_ips
-                    .get(&ip)
-                    .unwrap_or(&"Couldn't parse IP".to_string())
-                    .to_string()
-                    .yellow()
-                    .bold()
-                    .to_string()
-            );
-            let output = match result {
-                Ok(output) => output,
                 Err(e) => {
-                    error!("Can't access server: {}", e);
+                    error!("Error parsing regex. {}", e);
-                    continue;
+                    process::exit(1);
                 }
             };
-            if output.exit_status == 0 {
+            let matched: Vec<Host> = known_hosts
-                println!("Code {}", output.exit_status);
+                .clone()
-            } else {
+                .into_iter()
-                error!("Code {}", output.exit_status);
+                .filter(|r| re.is_match(&r.name.clone()))
-            };
+                .collect();
-            if !args.code {
+            all_hosts.extend(matched);
-                println!("STDOUT:\n{}", String::from_utf8(output.stdout).unwrap());
-                println!("STDERR:\n{}", String::from_utf8(output.stderr).unwrap());
-            }
         }
+        all_hosts
     } else {
-        warn!("Stopped");
+        // Use pattern expansion syntax (ranges and lists)
+        info!("Using string expansion to build server list.");
+        let mut all_hosts = Vec::new();
+        for expression in args.expression.iter() {
+            all_hosts.extend(expand_string(expression));
+        }
+        all_hosts
+    };
+
+    // Remove duplicate hosts while preserving original order
+    let matched_hosts: Vec<_> = hosts.into_iter().unique().collect();
+
+    // Log parallelism setting if not using the default
+    if args.parallel != 100 {
+        warn!("Parallelism: {} thread{}", &args.parallel, {
+            if args.parallel != 1 {
+                "s."
+            } else {
+                "."
+            }
+        });
+    }
+
+    // Store hosts with their original indices to preserve ordering
+    let mut host_with_indices: Vec<(Host, usize)> = Vec::new();
+    for (idx, host) in matched_hosts.iter().enumerate() {
+        host_with_indices.push((host.clone(), idx));
+    }
+
+    info!("Matched hosts:");
+
+    // Perform DNS resolution for all hosts in parallel
+    // Results are stored with original indices to maintain order
+    let resolved_ips_with_indices = Arc::new(Mutex::new(Vec::<(String, IpAddr, usize)>::new()));
+
+    host_with_indices
+        .par_iter()
+        .for_each(|(host, idx)| match lookup_host(&host.name) {
+            Ok(ips) if !ips.is_empty() => {
+                let ip = ips[0];
+                let mut results = resolved_ips_with_indices.lock().unwrap();
+                results.push((host.name.clone(), ip, *idx));
+            }
+            Ok(_) => {
+                let mut results = resolved_ips_with_indices.lock().unwrap();
+                results.push((
+                    host.name.clone(),
+                    IpAddr::V4(std::net::Ipv4Addr::new(0, 0, 0, 0)),
+                    *idx,
+                ));
+            }
+            Err(_) => {
+                let mut results = resolved_ips_with_indices.lock().unwrap();
+                results.push((
+                    host.name.clone(),
+                    IpAddr::V4(std::net::Ipv4Addr::new(0, 0, 0, 0)),
+                    *idx,
+                ));
+            }
+        });
+
+    // Sort hosts by original index to maintain consistent display order
+    let mut resolved_hosts = resolved_ips_with_indices.lock().unwrap().clone();
+    resolved_hosts.sort_by_key(|(_, _, idx)| *idx);
+
+    // Display all matched hosts with their resolved IPs
+    for (hostname, ip, _) in &resolved_hosts {
+        if ip.is_unspecified() {
+            error!("DNS resolve failed: {}", hostname.red());
+        } else {
+            info!("{} [{}]", hostname, ip);
+        }
+    }
+
+    // Filter out hosts that couldn't be resolved
+    let valid_hosts: Vec<(String, IpAddr, usize)> = resolved_hosts
+        .into_iter()
+        .filter(|(_, ip, _)| !ip.is_unspecified())
+        .collect();
+
+    // Exit if no valid hosts remain
+    if valid_hosts.is_empty() {
+        error!("No valid hosts to connect to");
+        process::exit(1);
+    }
+
+    // Find common domain suffix to optimize display
+    let hostnames: Vec<String> = valid_hosts
+        .iter()
+        .map(|(hostname, _, _)| hostname.clone())
+        .collect();
+    let common_suffix = find_common_suffix(&hostnames);
+
+    // Inform user about display optimization if common suffix found
+    if let Some(suffix) = &common_suffix {
+        info!(
+            "Common domain suffix found: '{}' (will be displayed as '*')",
+            suffix
+        );
+    }
+
+    // Ask for confirmation before proceeding (unless --noconfirm is specified)
+    if !args.noconfirm
+        && match Question::new(&*format!(
+            "Continue on following {} servers?",
+            &valid_hosts.len()
+        ))
+        .confirm()
+        {
+            Answer::YES => true,
+            Answer::NO => {
+                warn!("Stopped");
+                process::exit(0);
+            }
+            _ => unreachable!(),
+        }
+    {
+        info!("Run command on {} servers.", &valid_hosts.len());
+    }
+
+    // Execute commands using system SSH client
+    let batch_size = args.parallel as usize;
+    let mut processed = 0;
+
+    while processed < valid_hosts.len() {
+        let end = std::cmp::min(processed + batch_size, valid_hosts.len());
+        let batch = &valid_hosts[processed..end];
+
+        // Create a thread for each host in the current batch
+        let mut handles = Vec::new();
+
+        for (hostname, _, _) in batch {
+            let hostname = hostname.clone();
+            let username = args.username.clone();
+            let command = args.command.clone();
+            let common_suffix_clone = common_suffix.clone();
+            let code_only = args.code;
+
+            // Execute SSH command in a separate thread
+            let handle = thread::spawn(move || {
+                match execute_ssh_command(
+                    &hostname,
+                    &username,
+                    &command,
+                    &common_suffix_clone,
+                    code_only,
+                ) {
+                    Ok(_) => (),
+                    Err(e) => error!("Error executing command on {}: {}", hostname, e),
+                }
+            });
+
+            handles.push(handle);
+        }
+
+        // Wait for all threads in this batch to complete
+        for handle in handles {
+            handle.join().unwrap();
+        }
+
+        processed = end;
     }
 }