[PATCH] Loses a few pipes, passes shellcheck

[kseistrup]

The attached patch …

• adds SPDX tag SPDX-FileCopyrightText,
• explicitly disables irrelevant shellcheck checks,
• loses a few pipes,
• loses seemingly unnecessay call to sed in favour of ${variable//search/replace}, and
• double-quotes a few command substitutions, just to be on the safe side.

📎 shellcheck.diff.txt

It passes shellcheck and seems to work just fine here, but somebody should probably check it on their side.

---

Overview:

diff --git a/man.filter.dpi b/man.filter.dpi
index 5b9adbc..bc0fb3d 100755
--- a/man.filter.dpi
+++ b/man.filter.dpi
@@ -1,13 +1,14 @@
 #!/bin/bash
-# Copyright (c) 2023 Rodrigo Arias Mallo
+# SPDX-FileCopyrightText: Copyright (c) 2023 Rodrigo Arias Mallo
 # SPDX-License-Identifier: GPL-3.0-or-later
 
-IFS= read -d '>' auth # Ignore auth
-IFS= read -d '>' cmd
+# shellcheck disable=SC2034
+IFS= read -rd '>' auth # Ignore auth
+IFS= read -rd '>' cmd
 
 case "$cmd" in
   "<cmd='open_url' url='"*);;
-  *) echo $cmd; exit;;
+  *) echo "$cmd"; exit;;
 esac
 
 url=${cmd#"<cmd='open_url' url='"}
@@ -17,20 +18,20 @@ serve_404() {
   printf "<cmd='start_send_page' url='' '>\n"
   printf "Content-type: text/plain\r\n\r\n"
   manpage="$1"
-  apropos="$2"
-  if [ -z "$1" ]; then
+  test -n "$manpage" || {
     echo "Not found"
     exit 0
-  fi
-  echo "Manual page not found: $1"
-  if [ -n "$apropos" ]; then
+  }
+  apropos="$2"
+  echo "Manual page not found: $manpage"
+  test -n "$apropos" && {
     printf "\nRelated pages:\n"
     man -k "$apropos"
-  fi
+  }
 }
 
 inject_css() {
-  css=$(cat "$(dirname $(readlink -f $0))/style.css" | tr '\n' ' ')
+  css=$(tr '\n' ' ' < "$(dirname "$(readlink -f "$0")")/style.css")
   sed "s_</style>_$css\n</style>_"
 }
 
@@ -54,19 +55,23 @@ serve_manpage() {
   url="$1"
   ref="${url#"man:"}"
   # Reverse open(3) -> 3 open if given
-  manpage=$(echo "$ref" | sed 's/\(.*\)(\(.*\))/\2 \1/')
+  # shellcheck disable=SC2001
+  manpage=$(sed 's/\(.*\)(\(.*\))/\2 \1/' <<< "$ref")
   # If page not found, return 404
-  if [ -z "$manpage" ]; then
+  test -z "$manpage" && {
     serve_404
     exit 0
-  fi
+  }
+  # $manpage may contain both man section and man page
+  # shellcheck disable=SC2086
   if ! man -w $manpage 2>/dev/null; then
-    apropos=$(echo "$ref" | sed 's/(.*)//')
+    apropos="${ref%%(*}"
     serve_404 "$manpage" "$apropos"
   else
     printf "<cmd='start_send_page' url='' '>\n"
     printf "Content-type: text/html\r\n\r\n"
     unset MANROFFOPT
+    # shellcheck disable=SC2086
     man -Thtml $manpage | fix_br | inject_css | link_xrefs 2>&1
   fi
 }