From 62f7ea87871b861a079a64ef0e278370865498e4 Mon Sep 17 00:00:00 2001
From: Tom Ryder <tom@sanctum.geek.nz>
Date: Fri, 26 May 2017 20:34:16 +1200
Subject: Still tinkering with ?d.sh scripts

---
 sh/shrc.d/pd.sh | 49 ++++++++++++++++++++-----------------------------
 sh/shrc.d/rd.sh |  2 --
 sh/shrc.d/sd.sh |  2 --
 3 files changed, 20 insertions(+), 33 deletions(-)

diff --git a/sh/shrc.d/pd.sh b/sh/shrc.d/pd.sh
index ce43837b..e3a6daaa 100644
--- a/sh/shrc.d/pd.sh
+++ b/sh/shrc.d/pd.sh
@@ -2,39 +2,30 @@
 # use when you've got a file path in a variable, or in history, or in Alt+.,
 # and want to quickly move to its containing directory. In the absence of an
 # argument, this just shifts up a directory, i.e. `cd ..`
+#
+# Note this is equivalent to `ud 1`.
 pd() {
 
-    # Check argument count
+    # Check arguments; default to $PWD
     if [ "$#" -gt 1 ] ; then
         printf >&2 'pd(): Too many arguments\n'
         return 2
     fi
-
-    # Change the positional parameters from the target to its containing
-    # directory
-    set -- "$(
-
-        # Figure out target dirname
-        dirname=${1:-..}
-        dirname=${dirname%/}
-        dirname=${dirname%/*}
-
-        # Check we have a target after that
-        if [ -z "$dirname" ] ; then
-            printf >&2 'ud(): Destination construction failed\n'
-            exit 1
-        fi
-
-        # Print the target with trailing slash to work around newline stripping
-        printf '%s/' "${dirname%/}"
-    )"
-
-    # Remove trailing slash
-    set -- "${1%/}"
-
-    # If the subshell printed nothing, return with failure
-    [ -n "$1" ] || return
-
-    # Try to change into the determined directory
-    command cd -- "$@"
+    set -- "${1:-"$PWD"}"
+
+    # Make certain there are no trailing slashes to foul us up, and anchor path
+    # if relative
+    while : ; do
+        case $1 in
+            */) set -- "${1%/}" ;;
+            /*) break ;;
+            *) set -- "$PWD"/"$1" ;;
+        esac
+    done
+
+    # Strip a path element
+    set -- "${1%/*}"
+
+    # Try to change into the determined directory, or root if empty
+    command cd -- "${1:-/}"
 }
diff --git a/sh/shrc.d/rd.sh b/sh/shrc.d/rd.sh
index 3b699c0d..c4c1c063 100644
--- a/sh/shrc.d/rd.sh
+++ b/sh/shrc.d/rd.sh
@@ -1,4 +1,3 @@
-#
 # Replace the first instance of the first argument string with the second
 # argument string in $PWD, and make that the target of the cd builtin. This is
 # to emulate a feature of the `cd` builtin in Zsh that I like, but that I think
@@ -12,7 +11,6 @@
 #     $ rd usr opt
 #     $ pwd
 #     /opt/bin
-#
 rd() {
 
     # Check argument count
diff --git a/sh/shrc.d/sd.sh b/sh/shrc.d/sd.sh
index 561a77f4..af82b67e 100644
--- a/sh/shrc.d/sd.sh
+++ b/sh/shrc.d/sd.sh
@@ -1,4 +1,3 @@
-#
 # Shortcut to switch to another directory with the same parent, i.e. a sibling
 # of the current directory.
 #
@@ -31,7 +30,6 @@
 #     /tmp/tmp.ZSunna5Eup/a
 #
 # Seems to work for symbolic links.
-#
 sd() {
 
     # Check argument count
-- 
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