I'm writing a small utility tool for development to sync files over ssh. Normally I use ssh-agent set up in .bashrc file to connect to my dev server easily. I'd like to use exec in the script, but calling ssh-agent, every time I make a request sounds a bit inoptimal.
Is there a way I could execute the agent code once, and then have it working for all subsequent ssh requests I make? E.g. to spawn a shell process like a terminal emulator, and then use that process to execute a command, rather than invoking a new shell with each command.
The reason I want to do this, is I don't want to store the password in a config file.
You can create one ssh process, and then execute other commands using same process. Here is an example how to use it for bash. I'm creating a new bash shell and execugte the command ls -la and exit you can execute other commands.
const cp = require("child_process")
class MyShell {
constructor(command) {
this._spawned = cp.spawn(command, {
stdio: ["pipe", "pipe", "inherit"],
})
}
execute(command, callback) {
this._spawned.stdin.write(command + "\n")
this._spawned.stdout.on("data", (chunk) => {
if (callback) {
callback(chunk.toString())
}
})
}
}
var myShell = new MyShell("bash")
myShell.execute("ls -la", (result) => {
console.log(result)
})
myShell.execute("exit")
It seems like I can't access the $HOME property within my nodeJS app when running a child_process on my Linux machine:
var exec = require('child_process').exec
var testHome = `echo $HOME`
testHomeCmd = exec(testHome)
testHomeCmd.stdout.on('data', function (data) {
console.log(data)
})
Where the output I receive is: [17597]: /
If I run echo $HOME in terminal I receive:
$ echo $HOME
/home/cs4
Any thoughts?
I'm trying to change the directory of terminal using with Node.js program but not able to achieve it. Script is run as node app.js dir_name so first I'm creating the directory and then trying to change into that directory using cd command. Directory is created but the directory for terminal is not changed.
#!/usr/bin/env node
var platform = process.platform;
var figlet = require('figlet');
var chalk = require('chalk');
if(process.argv.length < 3){
console.log(
chalk.green(
figlet.textSync('mdcd', { horizontalLayout: 'full' })
)
);
console.log(chalk.red("Please provide a directory name"));
}else{
if(platform.includes("win")){
//console.log("Its Windows");
}else {
var exec = require('child_process').exec;
var command_1 = "mkdir "+process.argv[2];
var command_2 = "cd "+process.cwd()+"/"+process.argv[2];
exec(command_1, function (error, stdout, stderr) {
if(error){
console.log("Something bad happened"+error);
}else {
exec(command_2, function (error, stdout, stderr) {
if(error){
console.log("Something bad happened"+error);
}
});
}
});
}
}
command prompt directory from Node.js script
You cannot change the command prompt directory. Basically you have the process tree:
cmd / term
| -> NodeJs
You shouldn't change the working dir for cmd. However there are command you can execute to change the working dir of any process e.g. https://unix.stackexchange.com/a/282009
More
You can however change the the working dir for the nodejs process (which is what I suspect you want to do) using process.chdir https://nodejs.org/api/process.html#process_process_chdir_directory
I need to run a shell script file using nodeJS that executes a set of Cassandra DB commands. Can anybody please help me on this.
inside db.sh file:
create keyspace dummy with replication = {'class':'SimpleStrategy','replication_factor':3}
create table dummy (userhandle text, email text primary key , name text,profilepic)
You could use "child process" module of nodejs to execute any shell commands or scripts with in nodejs. Let me show you with an example, I am running a shell script(hi.sh) with in nodejs.
hi.sh
echo "Hi There!"
node_program.js
const { exec } = require('child_process');
var yourscript = exec('sh hi.sh',
(error, stdout, stderr) => {
console.log(stdout);
console.log(stderr);
if (error !== null) {
console.log(`exec error: ${error}`);
}
});
Here, when I run the nodejs file, it will execute the shell file and the output would be:
Run
node node_program.js
output
Hi There!
You can execute any script just by mentioning the shell command or shell script in exec callback.
You can execute any shell command using the shelljs module
const shell = require('shelljs')
shell.exec('./path_to_your_file')
you can go:
var cp = require('child_process');
and then:
cp.exec('./myScript.sh', function(err, stdout, stderr) {
// handle err, stdout, stderr
});
to run a command in your $SHELL.
Or go
cp.spawn('./myScript.sh', [args], function(err, stdout, stderr) {
// handle err, stdout, stderr
});
to run a file WITHOUT a shell.
Or go
cp.execFile();
which is the same as cp.exec() but doesn't look in the $PATH.
You can also go
cp.fork('myJS.js', function(err, stdout, stderr) {
// handle err, stdout, stderr
});
to run a javascript file with node.js, but in a child process (for big programs).
EDIT
You might also have to access stdin and stdout with event listeners. e.g.:
var child = cp.spawn('./myScript.sh', [args]);
child.stdout.on('data', function(data) {
// handle stdout as `data`
});
Also, you can use shelljs plugin.
It's easy and it's cross-platform.
Install command:
npm install [-g] shelljs
What is shellJS
ShellJS is a portable (Windows/Linux/OS X) implementation of Unix
shell commands on top of the Node.js API. You can use it to eliminate
your shell script's dependency on Unix while still keeping its
familiar and powerful commands. You can also install it globally so
you can run it from outside Node projects - say goodbye to those
gnarly Bash scripts!
An example of how it works:
var shell = require('shelljs');
if (!shell.which('git')) {
shell.echo('Sorry, this script requires git');
shell.exit(1);
}
// Copy files to release dir
shell.rm('-rf', 'out/Release');
shell.cp('-R', 'stuff/', 'out/Release');
// Replace macros in each .js file
shell.cd('lib');
shell.ls('*.js').forEach(function (file) {
shell.sed('-i', 'BUILD_VERSION', 'v0.1.2', file);
shell.sed('-i', /^.*REMOVE_THIS_LINE.*$/, '', file);
shell.sed('-i', /.*REPLACE_LINE_WITH_MACRO.*\n/, shell.cat('macro.js'), file);
});
shell.cd('..');
// Run external tool synchronously
if (shell.exec('git commit -am "Auto-commit"').code !== 0) {
shell.echo('Error: Git commit failed');
shell.exit(1);
}
Also, you can use from the command line:
$ shx mkdir -p foo
$ shx touch foo/bar.txt
$ shx rm -rf foo
I am trying to execute a child process in a different directory then the one of its parent.
var script = "drush language-add cn";
var folderDrush = "/data/www/sites/site_cn_country";
exec(script, {cwd:folderDrush} , function (err, stdout, stderr) {
if(err) {
sendErr("drush", stderr);
sendCommand(script);
sendCheck("drush", false);
}
});
This script returns:
The drush command 'language-add cs' could not be found. Run drush [31;40m[1m[error][0m cache-clear drush to clear the commandfile cache if you have installed new extensions.
But when I execute manualy, drush language-add work fine.
I test there commands too :
pwd : /data/www/sites/site_cn_country
id -u -n : root
ll : Command not found (why ? manually work...)
echo $SHELL : /bin/bash
This is not a direct answer, but you could change path before running the command:
var script = "cd /data/www/sites/site_cn_country && drush language-add cn";