---
title: wait — Wait for child processes to finish
date: 2026-10-20
time: 12:00
model: admin
category: programs
author_type: human
summary: A shell builtin that waits until child processes started by the shell have finished.
tags: program, Service and process management, wait
---

A shell builtin that waits until child processes started by the shell have finished.

## Basic Information

| Command Name | wait |
| --- | --- |
| One-line Introduction | A shell builtin that waits until child processes started by the shell have finished. |
| Provided by | Bash and POSIX shell builtin |
| Official Documentation | https://www.gnu.org/software/bash/manual/html_node/Job-Control-Builtins.html |
| Supported Operating Systems | Linux, macOS, BSD |
| Installation Status | Installed by default (shell builtin) |
| Category | Linux service and process management (tags: Process and resource management (tags: job control, synchronization, script)) |

## What is this command?

wait pauses a script until background children finish.

With a PID or job number it waits for that target only and returns its exit status.

## What problems does it solve?

- Run the next step only after parallel jobs finish.
- Check the exit code of a background job.
- Ensure completion before cleaning temp files.
- Fan out to several hosts and collect results.
## Key features

### Wait for all

Without arguments it waits for all children.

- **When to use**: When waiting for all parallel jobs
- **What you get**: Execution continues after all children end
- **Limitations**: The status reflects the last target
### Wait for a PID

A PID waits for that process only.

- **When to use**: When one job must complete
- **What you get**: That process exit status
- **Limitations**: An unknown PID fails immediately
### Collecting exit codes

Use $? to read the result after each wait.

- **When to use**: When failures must be distinguished
- **What you get**: Per-job success or failure
- **Limitations**: Waiting on many keeps only the last status
## Installation and usage

### Check whether it is installed

```
help wait
```

man bash   # wait is a shell builtin

## Real-world examples

### Wait for all

Wait until background jobs finish.

```
# Wait for every background job
wait
```

### Wait for a PID

Wait for one PID.

```
# Wait for a specific child
bg_pid=$!
wait $bg_pid
```

### Synchronize parallel jobs

Start several jobs and wait for all.

```
# Run three jobs in parallel, then wait
for h in web1 web2 web3; do ssh $h uptime & done
wait
```

---
Source (HTML): https://games.aidebatehub.com/programs/linux/services/wait.html
This file is an auto-generated Markdown twin of the DevHub document.