checked dependencies, made some optional, document optional dependencies

README.md

@@ -445,15 +445,49 @@ Verify support with:
 printf '\e[38;2;38;139;210mTrue colour test\e[0m\n'
 ```
 
-## 5. Contact and more information
+## 5. Optional dependencies
 
-### 5.1. New users
+profile is designed so that every external dependency is optional: all features
+degrade gracefully (an error message is shown and the specific function returns
+early) when a binary is absent. The table below lists packages that are **not**
+part of a standard minimal Linux installation (might differ from your actual
+distribution, some are still extremely common). Nothing in this list is required
+to load profile or use its core functions.
+
+| Binary | Typical package name | Distr. | Function(s) | Behaviour when absent |
+| --- | --- | --- | --- | --- |
+| `figlet` | `figlet` | all | `showinfo` | ASCII banner skipped |
+| `neofetch` | `neofetch` | all | `showinfo` | Falls back to `fastfetch`, then skipped |
+| `fastfetch` | `fastfetch` | all | `showinfo` | Falls back if `neofetch` absent; then skipped |
+| `jq` | `jq` | all | `myextip` | Raw JSON shown instead of formatted output |
+| `hexdump` | `util-linux` / `bsdmainutils` | all | `busy` | Error message, function returns 1 |
+| `numfmt` | `coreutils` ≥ 8.21 | all | `file_stats --min/--max` | Error message, function returns 1 |
+| `envsubst` | `gettext` | all | config loading | `$VAR` references in `profile.conf` values left literal |
+| `killall` | `psmisc` | all | `ku` | Falls back to `pkill` (procps); error if both absent |
+| `pkill` / `pgrep` | `procps` / `procps-ng` | all | `ku`, `ppg`, `gpid` | `ku` falls back to `killall`; `ppg`/`gpid` fall back to `ps + awk` |
+| `pigz` | `pigz` | all | `taz` (gzip) | Falls back to `gzip` (slower, single-thread) |
+| `plzip` | `plzip` | all | `taz` (lzip) | Falls back to `lzip` |
+| `lzip` / `plzip` | `lzip` | all | `taz`/`utaz` (.lz) | Error message if neither is available |
+| `xz` | `xz-utils` / `xz` | all | `taz`/`utaz` (.xz) | Error message |
+| `unrar` | `unrar` / `unrar-free` | all | `utaz` (.rar) | Error message |
+| `unarj` | `arj` | all | `utaz` (.arj) | Error message |
+| `lha` | `lhasa` | all | `utaz` (.lzh) | Error message |
+| `unace` | `unace` | all | `utaz` (.ace) | Error message |
+| `7z` | `p7zip-full` | all | `taz`/`utaz` (.7z) | Error message |
+| `cabextract` | `cabextract` | all | `utaz` (.cab) | Error message |
+| `rpm2cpio` | `rpm` | all | `utaz` (.rpm) | Error message |
+| `nix-locate` | `nix-index` | NixOS | `pkgf` | Error: unsupported package manager |
+| `qfile` | `gentoolkit` | Gentoo | `pkgf` | Error: unsupported package manager |
+
+## 6. Contact and more information
+
+### 6.1. New users
 
 If you use (or plan to use) `profile`, I'll be happy if you simply mail me to
 let me know, especially if you don't plan to contribute. If you plan to
 contribute, I'll be twice happier for sure!
 
-### 5.2. Bugs
+### 6.2. Bugs
 
 **profile** bug tracker is hosted on its Gitea instance. Check the
 <https://git.geoffray-levasseur.org/fatalerrors/profile> page. If you find a bug,
@@ -468,7 +502,7 @@ have not tested the same code under a real Unix environment.
 Check the [FAQ](./doc/FAQ.md) and the [to-do list](./doc/todo.md) before
 sending any feature request or bug report, as it might already be documented.
 
-### 5.3. How to contribute?
+### 6.3. How to contribute?
 
 You are free to improve and contribute as you wish. If you have no idea what to
 do or want some direction, you can check the [to-do list](./doc/todo.md),

profile.d/filefct.sh

@@ -471,6 +471,12 @@ file_stats()
     fi
 
     # Minimum/maximum size filters (evaluated in bytes)
+    if [[ -n "$min_size" || -n "$max_size" ]]; then
+        if ! command -v numfmt >/dev/null 2>&1; then
+            disp E "file_stats: --min/--max require 'numfmt' (GNU coreutils). Please install it."
+            return 1
+        fi
+    fi
     if [[ -n "$min_size" ]]; then
         find_cmd+=(-size +"$(numfmt --from=iec "$min_size")"c)
     fi

profile.d/fun.sh

@@ -94,6 +94,11 @@ busy()
     delay_s=$(awk "BEGIN{
         printf \"%.3f\", $delay_ms / 1000 }")
 
+    command -v hexdump >/dev/null 2>&1 || {
+        disp E "busy: 'hexdump' is required but not installed (util-linux or bsdmainutils)."
+        return 1
+    }
+
     # Monitor /dev/urandom
     (
         hexdump -C < /dev/urandom | grep -iF --line-buffered "$pattern" | \

profile.d/processes.sh

@@ -199,7 +199,7 @@ export -f ppn
 
 # ------------------------------------------------------------------------------
 # Get PID list of the given process name
-# Usage: ppid <process_name [process_name2 ...]>
+# Usage: gpid <process_name [process_name2 ...]>
 gpid()
 {
     local PARSED
@@ -361,16 +361,33 @@ ku()
             disp E "User '$u' does not exist."
             return 1
         else
-            local cmd=(killall)
+            local cmd
 
-            if [[ ${#signal_opt[@]} -gt 0 ]]; then
+            # killall (psmisc) preferred; fall back to pkill (procps-ng).
-                cmd+=("${signal_opt[@]}")
+            if command -v killall >/dev/null 2>&1; then
-            elif [[ -n "${KU_DEFAULT_SIGNAL:-}" ]]; then
+                cmd=(killall)
-                cmd+=("-${KU_DEFAULT_SIGNAL}")
+                if [[ ${#signal_opt[@]} -gt 0 ]]; then
+                    cmd+=("${signal_opt[@]}")
+                elif [[ -n "${KU_DEFAULT_SIGNAL:-}" ]]; then
+                    cmd+=("-${KU_DEFAULT_SIGNAL}")
+                fi
+                cmd+=(-u "$u")
+            elif command -v pkill >/dev/null 2>&1; then
+                cmd=(pkill)
+                # Translate killall's -s SIGNAME form to pkill's -SIGNAME form.
+                if [[ ${#signal_opt[@]} -eq 2 && "${signal_opt[0]}" == "-s" ]]; then
+                    cmd+=("-${signal_opt[1]}")
+                elif [[ ${#signal_opt[@]} -gt 0 ]]; then
+                    cmd+=("${signal_opt[@]}")
+                elif [[ -n "${KU_DEFAULT_SIGNAL:-}" ]]; then
+                    cmd+=("-${KU_DEFAULT_SIGNAL}")
+                fi
+                cmd+=(-u "$u")
+            else
+                disp E "ku: neither 'killall' (psmisc) nor 'pkill' (procps) is available."
+                return 1
             fi
 
-            cmd+=(-u "$u")
-
             if (( dry_run )); then
                 printf "DRY-RUN: "
                 printf "%q " "${cmd[@]}"

profile.sh

@@ -244,7 +244,10 @@ parse_conf()
 
             # Correctly interpretet internal variables (e.g. $HOME)
             if [[ "$value" == *\$* ]]; then
-                value=$(envsubst <<< "$value")
+                if command -v envsubst >/dev/null 2>&1; then
+                    value=$(envsubst <<< "$value")
+                fi
+                # If envsubst is unavailable, $VAR references are left as-is.
             fi
 
             # Strip quotes (handling both " and ')