Bash functions: add stdbuf() for NetBSD and OpenBSD.

CHANGELOG.md

@@ -13,6 +13,7 @@ Although Moulti's Python packages, modules and functions are obviously available
 - bash functions:
   - `moulti_process_lines()` helps to turn arbitrary output into Moulti steps
   - `moulti_check_requirements()` helps to ensure required commands are available
+  - `stdbuf()` replaces the `stdbuf` utility on NetBSD and OpenBSD
 
 ### Changed
 

Documentation.md

@@ -665,9 +665,9 @@ Per se, Moulti does not:
 - wrap lines (use e.g. `fold`)
 - distinguish stdout from stderr (it reads a single stream anyway; use e.g. `stderred`)
 - tweak the output buffering policy of other processes:
-  1. look for command-line options and environment variables that explicitly address the issue, e.g. `--line-buffered` or `PYTHONUNBUFFERED=1`
-  2. use `LD_PRELOAD`-based tools such as `stdbuf` or [cvolny/faketty](https://github.com/cvolny/faketty)
-  3. use tools that allocate a [pty](https://en.wikipedia.org/wiki/Pseudoterminal), e.g. `script` or [dtolnay/faketty](https://github.com/dtolnay/faketty):
+  1. look for command-line options and environment variables that explicitly address the issue, e.g. `--line-buffered`, `PYTHONUNBUFFERED=1` or `STDBUF` (NetBSD-specific)
+  2. use `LD_PRELOAD`-based tools such as `stdbuf` (from the `coreutils` package) or [cvolny/faketty](https://github.com/cvolny/faketty)
+  3. use tools that allocate a [pty](https://en.wikipedia.org/wiki/Pseudoterminal), e.g. `script`, `unbuffer` (from the `expect` package) or [dtolnay/faketty](https://github.com/dtolnay/faketty):
   ```bash
   script --quiet --return --command 'your command here' /dev/null | moulti pass your_step
   ```

examples/moulti-functions.bash

@@ -153,6 +153,22 @@ function moulti_type {
 	done
 }
 
+if [ "$(uname)" == 'NetBSD' ]; then
+	function stdbuf {
+		# Ignore arguments and request line buffering for stdout:
+		while [[ "$1" =~ ^- ]]; do shift; done
+		STDBUF1='L' "$@"
+	}
+elif [ "$(uname)" == 'OpenBSD' ]; then
+	if moulti_tool_is_available unbuffer; then
+		function stdbuf {
+			# Ignore arguments and call unbuffer:
+			while [[ "$1" =~ ^- ]]; do shift; done
+			unbuffer "$@"
+		}
+	fi
+fi
+
 MOULTI_NEW_STEP_PATTERN='^([-=#@]+)(\s*)(.+?)\2\1$'
 
 function moulti_process_lines {

examples/progressbar.bash

@@ -6,7 +6,7 @@ export MOULTI_INSTANCE='generate-ssh-keys'
 
 set -e
 source moulti-functions.bash
-moulti_check_requirements stdbuf ssh-keygen || true
+moulti_check_requirements 'stdbuf|unbuffer' ssh-keygen || true
 
 # Run moulti_exec with stdbuf and a simplified ssh-keygen command in the title:
 function ssh_keygen {