Check if bash script is running. It represents a particular running program or command.

Check if bash script is running I want to avoid printing of ANSI escape sequences in . g. Initially, we discussed the EUID shell variable for verification. the program always touches file /home/someuser/a, and nothing else Nov 22, 2021 · So if another program with the same basename is already running, your program will (wrongly) assume that it is already running and thus not start. We can easily check whether a process is currently running or not using the tasklist toolkit. /xyz. If they don't, I'd rather have the script exit rather than prompting them for a password. Whether you’re a seasoned programmer or just beginning your journey into the world of scripting, understanding how to run Bash scripts is essential. Aug 30, 2021 · Sorry for my poor english ;) I need to check if a script is already running or not. Just to be clear: What How can I launch a process in background and check when it ends within a bash script? My idea is a script like this: launch backgroundprocess & while [ Process is running ];do echo "PROCES Master the art of a bash syntax checker with our clear guide. bashrc if it's the latter. Oct 27, 2022 · Recent WSL Releases: wslinfo In recent WSL releases, the wslinfo command has been added and can be used to check certain features of WSL from within the running distribution. For example, I might want to start the container if it's not already running, or query some piece of information about it like what ports are exposed. Then have a cron-job start it periodically. Using a Bash if Statement Apr 26, 2025 · Bash scripting is a powerful tool that developers can leverage to automate tasks on Unix and Linux systems. 04, but I imagine it's similar for al Jan 8, 2023 · How to check if process is already running in bash Linux? Determine whether multiple instances of same script or process is still running in background? Mar 18, 2024 · Learn various commands to check if a process is running in Linux. Here is a pseudo I'm running a script called RecordProcessor. Open another terminal session and try running the script again and it should say it's already running. 2. This works with if process is not running or process is running multiple times: bash 62 For the record, if the script is run with set -e (or #!/bin/bash -e) and you therefore cannot check $? directly (since the script would terminate on any return code other than zero), but want to handle a specific code, @gboffis comment is great: I have a script where I do not want it to call exit if it's being sourced. Ideal for both novices and experts. rc or such), or by checking the results (e. Jun 26, 2011 · I need to check the existence of an input argument. What is the proper way to detect the operating system in a Bash script? Aug 18, 2025 · In this chapter of bash beginner series, you'll learn about using if-else, nested if else and case statements in bash scripts. This is an example of a bash script which checks for some running process (daemon or service) and does specific actions (reload, sends mail) if there is no such process running. e. sh bash shell. Things I've found I have managed to find several other Stack Overflow questions, but they relate to detection of operating systems: - How to check if running in Cygwin, Mac or Linux? - How to detect the OS from a Bash script? Jul 30, 2016 · What I want to do is to read this script line by line, check if what I have read so far is a complete bash expression; if it is complete, eval it; otherwise keep on reading the next line. py. If update. When I run the ps command from the command-line, the $? is correctly set, but @eiswezinoo if you want to test if it's working or not, try: Implementing the code above in your script. Master the art of process management with our guide on bash check if process is running. Aug 25, 2025 · While commands like ps, pgrep, and pidof can help check whether a script is running, they’re not bulletproof. Mar 18, 2024 · In this tutorial, we’ll learn how we can validate the syntax of a Bash script without running it. pid (the $() syntax I'm writing a simple bash script, but I need it to check whether it's being run as root or not. Instead of using the UID, you can also match the logged-in user name. For example, if we try to run [[ -f ~/. Ways to Check if a Process is Running Using the ps Command The ps command is a powerful tool that allows you to check if a process is running on your system. Master the art of Bash scripting using ShellCheck, a static analysis tool that acts like a spell-checker for shell scripts. I have a user in sudo group - this always returns true - is sudo - whether or not I run using sudo. When the script is working, check that it still runs without the settings in your . Discover how to handle errors gracefully in bash if command fails. I guess a better example would be: command && echo "success: $?" Jun 2, 2020 · How to find out if running script/command as root/sudo using bash script Ask Question Asked 5 years, 5 months ago Modified 5 years, 5 months ago Nov 4, 2016 · I would look at the init locations and see if the program is set there to run. Jul 23, 2025 · A bash script is a text file that contains a sequence of commands that are executed by the bash shell, a Unix-based command-line interface. pid) else # Deal with the fact that the process isn't running # i. I know there's probably a very simple way to do that, but I have no idea how. Explore powerful techniques to validate your scripts and streamline your workflow. In this comprehensive guide, we will explore the ins and outs of checking command success in Bash. Nov 28, 2021 · How do I detect from within a shell script if its standard output is being sent to a terminal or if it's piped to another process? The case in point: I'd like to add escape codes to colorize output May 11, 2017 · 83 Programs to monitor if a process on a system is running. If this is in a script (which I assume is the case as you're worried about printing to stdout) then the following would be how you could do it: if ps -p $(cat something. pid) > /dev/null 2>&1 then kill $(cat something. id -u If run as root, this command will return an id of 0. These scripts, written in shell programming languages like Bash, allow users to execute a sequence of commands efficiently. SECONDS is a special variable in bash that contains the number of seconds since the script has started. This guide will walk you through how to use if statements in Bash to verify sudo/root access, with clear examples and best practices for beginners. Whether it’s for automated backups, managing config files, or running regular system checks, mastering this skill will make your Bash scripts run like clockwork. Use the sleep command in your script to make it process longer than it normally would. May 11, 2017 · 83 Programs to monitor if a process on a system is running. As for detecting if your script is executed or sourced, this is especially important if your script can be sourced by a user directly in their shell. The whoami command provides the currently logged user name. I execute this scripts. Using /usr/env/bin bash prevents you from determining which script is running. I know how to do this manually, with $ service [service_name] status. Apr 15, 2020 · How do I check if a script is running and pause until that instance has completed to run again? Ask Question Asked 5 years, 5 months ago Modified 5 years, 5 months ago 3 I would like to write a cross-platform script using shell so I can run it on linux, mac os and windows. [ is itself a command, very nearly equivalent to test. In your own script, you can check if the script is already running and do nothing (or safely quit this instance) if another instance is running already. Some programs use pidfile (more detail here). bash_login files in version control so that I can use them between all the computers I use. It's probably the most common command to use in an if, which can Feb 5, 2016 · How can I determine if a script was invoked from a command line or via double-click in file manager (Nautilis)? If the former, I still have a command prompt when the script finishes, but if it was Nov 16, 2021 · When we're writing a custom script we need to make sure that we're we need to make sure that our code runs properly in the shell in which we're running on. Honestly, if the program somehow could run, but you don't know whether it run or not, the only chance of seeing if it did run is to either check if it had a way to run (e. This script provides a flexible and user-friendly way to determine whether a specific process is running. Oct 21, 2023 · Learn the methodology to determine if your bash script is running in a Linux environment. sh This is bash $> dash test_script Feb 25, 2014 · 33 How do you check if a process on Mac OS X is running using the process's name in a Bash script? I am trying to write a Bash script that will restart a process if it has stopped but do nothing if it is still running. 15-klk my platform architecture is armv7l GNU/Linux I am trying to check if my process is running or not : I tried this: #!/bin/sh service= Can I make a bash command line that only runs a certain command if the process is not already running (in the background)? How do I check*, if a command is already running? May 21, 2022 · 7 I would like to have a shell script that checks if a particular container is running. Mar 15, 2019 · check if service is running via bash script Asked 6 years, 8 months ago Modified 6 years, 8 months ago Viewed 2k times May 23, 2023 · That immediately sets you up for wanting your script to be called in 2 different ways which is running the script normally (ie. Apr 1, 2015 · I have a customised linux version, kernel version is 4. The problem is that with the below code, -since I'm running this within the same script- the script kills itself too because it sees a script already running. It represents a particular running program or command. Jul 6, 2019 · The watershed util, (in Debian -based distros install it with apt install watershed), might be useful. This guide provides essential techniques to enhance your scripting skills. Feb 17, 2024 · Here explore a shell script designed to check the status of a process based on either its process ID (PID) or name. Thus we can make a script like this, #!/bin/bash if grep -q 'bash' /proc/$$/cmdline ; then echo "This is bash" else echo "This is some other shell" fi Here's a test of the same script: $> bash test_script. Knowing whether a command succeeded or failed is critical for scripting and automating tasks effectively. 0. One common use-case is to source a script in another script, allowing the sharing of variables and functions between them. sh and I'm writing another script to check whether RecordProcessor. How can a shell/bash script detect whether it is running in C Mar 1, 2014 · Is there a script or a way in linux that when I try to execute a shell script/process, if the same is running, it will prompt that same is running and will exit otherwise it will continue. Discover simple techniques to streamline your scripts. /usr/bin/wslinfo is always a symlink to the WSL-injected Use /proc/[PID]/cmdline to see what the script is being run with and test for what it contains. How can I determine the current shell I am working on? Would the output of the ps command alone be sufficient? How can this be done in different flavors of Unix? Can I make a bash command line that only runs a certain command if the process is not already running (in the background)? How do I check*, if a command is already running? May 21, 2022 · 7 I would like to have a shell script that checks if a particular container is running. sh" I couldn't find it there except for the grep which is being run with that string as a para Nov 8, 2023 · As a Linux system administrator, being able to check the status and exit codes of commands you run is an indispensable skill. Aug 14, 2018 · How can I tell if a script was called from systemd or from a user? I created a service for an old school daemon. Here is an example of checking if running as root in a bash script (using `id -u` inline to do so): Apr 22, 2010 · I think I have a shell script (launched by root's crontab) that's stuck in a loop. The “root” user’s UID is always 0 on the Linux systems. The lock directory pattern is the most reliable, portable, and safe method to ensure your script only runs once. We just switched to systemd and some of my admin like to call the rc-script directly. That‘s where the humble if statement comes in – it‘s the backbone of decision-making in Bash. Apr 26, 2025 · Here the EUID is the system variable that stored the user id (UID) of the currently logged-in user. If it doesn't find one, we exit the script. Apr 25, 2012 · I am wondering what's the easiest way to check if a program is executable with bash, without executing it ? It should at least check whether the file has execute rights, and is of the same archite May 16, 2017 · In a third screen I want to run a script which checks if the both python programs are running and also if they are running correctly (maybe check console output to determine if the output is as expected). Bash Check Essentials: Mastering Command-Line Validation Master the art of bash check with our concise guide. Check if the process of this pid is running. check_process(){ Jun 15, 2010 · In a bash script, I want to do the following (in pseudo-code): if [ a process exists with $PID ]; then kill $PID fi What's the appropriate expression for the I have a shell script that is used both on Windows/Cygwin and Mac and Linux. Apr 4, 2014 · How can I check if a script (e. Oct 4, 2018 · I have a python script named update. Mar 7, 2011 · The original question asked was "How to check if a command succeeded?", this was based on previous answers. problem is check condition always become true (because to check the condition require to run script) and it always show me "Already script running" message. The problem is I have some OS specific aliases so I was looking for a way to determine if the script is running on Mac OS X, Linux or Cygwin. In this tutorial, we’ll discuss how to check if a command was executed successfully or not in Linux. Bash. Nov 5, 2015 · I have to write a bash script that launches a process in background in accordance to command line argument passed and returns if it were successfully able to run launch the program. sh via . This works with if process is not running or process is running multiple times: bash Nov 28, 2021 · How do I detect from within a shell script if its standard output is being sent to a terminal or if it's piped to another process? The case in point: I'd like to add escape codes to colorize output Aug 30, 2021 · Sorry for my poor english ;) I need to check if a script is already running or not. This appears to be more reliable than the other methods, and it seems that it return an id of 0 even if the script is run through sudo. This article focuses on master file, directory, and variable checks using if, test, and conditional expressions. Nov 6, 2018 · I want to know from within the script if that script already running. So the function should do: Feb 11, 2024 · To check for errors and debug a Bash script, you can use the -x option with the bash command. sh &, is already running or not is to use jobs builtin command. I had written a bash script but it doesn't seem to work. Bash scripts are used to automate tasks, create utility scripts, and perform a wide range of other functions in the command-line environment. profile -file on every login, to get instant notification on each login. clear up the pid file fi The ps -p looks for a process with the pid specified in something. Monitor resource usage and automate process monitoring with bash scripts and cron jobs. The "bash shell check" refers to verifying the syntax and potential issues in a Bash script to ensure it runs smoothly without errors. Each of the . The plain bash is a non-login interactive shell - the tty pts/34 is the same so you can tell that it is the parent shell (or distant grand-parent) of the myscript. Is there any variable that cron sets when it runs a program ? If the script is run by cron, I would like to skip some parts; otherwise invoke those parts. Each process has its unique process ID (PID). bashrc, such as the path to supervisorctl. You‘ll […] How would I validate that a program exists, in a way that will either return an error and exit, or continue with the script? It seems like it should be easy, but it's Feb 21, 2022 · Given a process or application (. Mar 18, 2017 · This doesn't work if the user is in the sudo group but is not actively running this script as sudo. How do I list running scripts and how can I kill them? I'm running Ubuntu 9. was registered in some local. But at times, it’s crucial to know whether a Bash script has been sourced or executed directly. There are several different features that can be used here: In WSL pre-release 2. I don't want to use a lock file, as it can be tricky (ie: if my script wrote a lock file, but crashed, I will con To avoid this, it’s critical to check whether a script is running with sudo (or as the root user) at the start. By using the ps command, you can Jun 8, 2016 · 21293 pts/34 Ss+ 0:00 bash The -bash is a login shell. It doesn't work since the ps command always returns exit code 1. In this case, pgrep would not detect the process Nov 8, 2023 · As a Linux system administrator, being able to check the status and exit codes of commands you run is an indispensable skill. Jan 28, 2025 · My very rusty brain, google, and ChatGPT gave me a list of checks to test if running in a terminal, but none are giving correct results across all 4 calls. May 1, 2017 · In a script, I need to check: a) Is the docker engine running? b) Given a container name, is that docker container running? This is easiest done with pgrep and pkill: if pgrep process_name 2>/dev/null; then echo "Terminating process_name" pkill process_name fi As user @OrangeDog points out in the comments, there is the theoretical possibility of this shell code failing to terminate the process process_name if the process spawns inbetween the call to pgrep and pkill. It is better to have your script check a pid-file upon startup: Read a pid from a file with a fixed name. The $$ variable will give us the PID of the running shell. It needs slightly different variables for each versions. Python can be used to check if a process is running May 16, 2017 · In a third screen I want to run a script which checks if the both python programs are running and also if they are running correctly (maybe check console output to determine if the output is as expected). I heard people recommend using "Puppet" to check, but I haven't found a useful tutorial so far. Each of the May 7, 2022 · First make and test a script without crontab that performs the actions you want. In this section, we will discuss different methods for ignoring errors in Bash and provide examples of how to implement them. Feb 8, 2021 · No, that checks if the script is already running before launching it. A regular look on ps won't cut it as it get's different arguments in different order. May 30, 2013 · I built on his answer and built a login script, which shows if my programs are still running. Oct 7, 2017 · My problem: I'm writing a bash script and in it I'd like to check if a given service is running. Shell script to View all running processes Aug 24, 2019 · In gist, I am trying to get my bash scripts and Vim to behave differently when running in VS Code's integrated terminal. check if PID still running if yes then keep checking if not then echo PID has finished and send simple email or Check (learning bash) I was trying to check the bash version so I typed /bin/bash -v. When you execute a program, the operating system creates a process to run that program. Learn how to install it on Linux systems and integrate it into your development workflow to ensure script safety and quality. Nov 19, 2024 · In the world of Bash scripting, enhancing your scripts with conditional checks is essential for creating robust and dynamic applications. Apr 13, 2016 · I am new to bash scripting and trying to figure out why the below script is outputting that Apache server is not running whereas it is running properly. May 31, 2010 · I tried running a script using nohup like, nohup script. This exit status of the command gives us an idea about the success, failure, or other unexpected results that the command may return. I'm using cygwin on windows to make this possible. If under init. bashrc, and other files sourced from it). zshrc ]] && source ~/. How to conditionally do something if a command succeeded or failed That's exactly what bash's if statement does: if command ; then echo "Command succeeded" else echo "Command failed" fi Adding information from comments: you don't need to use the [ ] syntax in this case. Dec 8, 2014 · I am running a shell script in server with command line arguments as follows. 4, the /usr/bin/wslinfo command was added with the --networking-mode switch. This option enables debugging output, showing each command as it is executed. ShellCheck helps detect issues, offers suggestions, and supports various shells. sh What is Bash Shell Check? Bash shell check refers to the process of analyzing a Bash script for syntax errors, potential bugs, and adherence to best practices. We’ll take a closer look at some of the Bash and third-party utilities that can be used for this purpose. The right way to check in the current bash session if a process started in background, like sh abc. ShellCheck is an open source static analysis tool that automatically finds bugs in your shell scripts. Mar 18, 2024 · Learn various commands to check if a process is running in Linux. With a simple file check in place, your scripts run smoothly, avoiding errors and preventing the headaches that come with debugging complex systems. py, and I want to use another python script to check whether the script is running or not. 1. . Tasklist allows us to check for current processes. Jul 6, 2024 · In this article, we learned ways to check if a script was being run as root on a Linux system. Nov 12, 2007 · Explains how to check if a bash shell script is being run or executed by the root user account under Linux, macOS, Unix and BSD. /demo). . Feb 19, 2025 · Learn how to check if a program exists in a Bash script using simple commands like command -v, which, and type. sh DD 10 20 I want to write some check code inside the script that it will detect if same script is running in Mar 23, 2024 · Learn how to check if a process is running on Linux using various commands like ps, top, pgrep, pidof, and systemctl. Also check that your script doesn't write to stdout, perhaps introduce a logfile. In this guide, we'll show the steps to check a shell script in Linux before running it, ensuring it is error-free and performs as Nov 27, 2019 · I'm able to check whether a bash script is already running or not and I want to kill the script if it's already running. The tests are in check-term and there is a calling script check-term-driver, both below. Mar 18, 2024 · When we execute a command in Linux, we get the system response, called an exit code or exit status. bash -n your_script. False if file_descriptor is not a valid file descriptor number, or if file descriptor number file_descriptor is not open, or if it is open but is not associated with a Mar 15, 2019 · check if service is running via bash script Asked 6 years, 8 months ago Modified 6 years, 8 months ago Viewed 2k times May 23, 2023 · That immediately sets you up for wanting your script to be called in 2 different ways which is running the script normally (ie. 04 @Brian Fitzgerald 's pgrep script does work. That outputted a whole lot of text to the screen (contents of . Ubuntu 20. Ensure your scripts run flawlessly with helpful tips and practical examples. Execute your script from the command line. Step-by-step examples. May 25, 2010 · I wrote a bash-script to check if a process is running. I have the following script if [ "$1" -gt "-1" ] then echo hi fi I get [: : integer expression expected How do I check the input argument1 fi Jun 1, 2024 · I want to check if the current user running a BASH shell script has access to passwordless sudo or not. Feb 21, 2022 · Check processes that run in the current shell We use the ps command to see the currently running processes in the shell. I thought of checking if $0 == bash but this has problems if the script is sourced from another script, or if the user Instead of having an external bash script check it, you can have your own program do that. bat. Jul 23, 2025 · Shell scripts are a powerful way to automate tasks and manage system processes in Linux. How can I know if the Bash script is star Oct 22, 2023 · To determine if a Bash script failed or succeeded, you can check its exit status, return code, or use conditional statements to check the execution result of specific commands. Example: In this example, we have created a batch script by the name process. zshrc; in bash shell it'll throw the following error. Description: reduce superfluous executions of idempotent command watershed may be run around a command such that any further attempts to run the command while another copy is running will only result in one initial further attempt. You can use commands like ‘ps’, and ‘top’ to see running process details. Syntax : ps Example shell script : #!/bin/bash function proCheck () { ps } proCheck Output : Check all running processes in the Terminal To view all the running processes in the terminal, we use the ps command followed by -A or -e. To use it, the first instance, (and all further attempts Mar 18, 2023 · How can i check in a script if a certain process (PID) is still running? e. Script is stored in crontab and runs once every minute. sh & When I tried ps -ef | grep "script. Is there a way to detect if the shell if running on windows in shell script? Thanks! Jan 18, 2024 · In Linux, the process is executing an instance of a running program. Apr 25, 2009 · 129 I have a python daemon running as a part of my web app/ How can I quickly check (using python) if my daemon is running and, if not, launch it? I want to do it that way to fix any crashes of the daemon, and so the script does not have to be run manually, it will automatically run as soon as it is called and then stay running. Feb 23, 2023 · If you service is under systemd control, use systemctl status SERVICE. Even though that process is running, if i do grep I'm not able t Nov 2, 2024 · Executing a Bash script effectively can significantly streamline your workflow. sh is running or not. Other posts (see below) ask and answer how to know whether the user is actually running as May 21, 2025 · Hey there, fellow coder! Have you ever found yourself writing a Bash script and wondering how to make it smarter? Whether you‘re automating system tasks, processing data, or building development tools, mastering conditional logic is your gateway to creating truly powerful scripts. However, there are some custom commands that I need to execute on windows only. bashrc) if I'm running in interactive mode, or, say, executing a command over ssh. exe) file, the task is to create a batch script that checks whether the process is running or not and output the same. 840 I would like to keep my . May 30, 2010 · How can I tell (in ~/. How can I determine if a process is running or not and then have a bash script execute some stuff based on that condition? For example: if process abc is running, do this if it is not running, do Oct 7, 2017 · My problem: I'm writing a bash script and in it I'd like to check if a given service is running. Jan 31, 2019 · I have a bash script that will only work with root privileges, so I want to test whether the user has them. Aug 18, 2025 · In this chapter of bash beginner series, you'll learn about using if-else, nested if else and case statements in bash scripts. Nov 2, 2017 · isatty is a function for checking this, and the -t flag of the test command makes that accessible from a shell script: -t file_descriptor True if file descriptor number file_descriptor is open and is associated with a terminal. bashrc and . I'm interested in whether it ran at any time during the current shell session. d, you will have a "S*service" script which has a status option. py doesn't run or error, then the script will run update. /demo) or sourcing it from another script (ie. I don't believe the code above is checking for arguments Nov 7, 2012 · I am trying to automatically check if a process is running or not and have to perform next steps accordingly. Jul 23, 2025 · While it is important to handle errors in Bash scripts, there may be certain situations where you want to ignore errors and continue running the script. a bash script) is running (in the background) using command line‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌ To clarify, are you asking how to check if a certain script execution was successful or not in Bash? Jun 29, 2016 · Now I wonder how can I check if these two programs are running, and if not, run the script to start them. The below script will check if the script is running as a root user or not. pgrep test checks for a process named test. Apr 9, 2014 · In above script i want to check if this script previously running or not if running then not run it again. Next add the script to crontab. nwl lqqu gmgze exj inatj uvfmj goku qwrmu pptfry gysmjry hqvbyzb pabl hroyuyw wopmdf xshde