Initial version of cdlog.

1 files changed, 114 insertions, 0 deletions

diff --git a/cdlog.sh b/cdlog.sh
new file mode 100644
index 0000000..5e53e4b
--- /dev/null
+++ b/cdlog.sh
@@ -0,0 +1,114 @@
+# License at bottom.
+
+# Initialize cdlog the first time.
+if [ -z "$c1" ] ; then
+  c9=
+  c8=
+  c7=
+  c6=
+  c5=
+  c4=
+  c3=
+  c2=
+fi
+
+# One-letter nicknames for most recent four dirs.
+cdlog_nicks()
+{
+  x=$c1
+  y=$c2
+  z=$c3
+  w=$c4
+}
+
+# Change to directory: this is aliased to cd command.
+cdlog_chdir()
+{
+  local cur=$PWD
+
+  if command cd "$@" && [ "$PWD" != "$cur" ]; then
+    # only if we successfully change to a different
+    # directory do the following
+
+    if [ "$cur" == "$c2" ] && [ "$PWD" == "$c1" ] ; then
+      # Special case: if we changed to the directory that is second
+      # in the cdlog, then just swap between those two.
+      c2=$PWD
+      c1=$cur
+    else
+      # Otherwise rotate through all
+      c9=$c8
+      c8=$c7
+      c7=$c6
+      c6=$c5
+      c5=$c4
+      c4=$c3
+      c3=$c2
+      c2=$c1
+      c1=$cur
+    fi
+
+    cdlog_nicks
+  fi
+}
+
+# Change to most recent diretory in cdlog and remove it
+# from the log.
+cdlog_pop()
+{
+  if [ -n "$c1" ] && command cd "$c1"; then
+    c1=$c2
+    c2=$c3
+    c3=$c4
+    c4=$c5
+    c5=$c6
+    c6=$c7
+    c7=$c8
+    c8=$c9
+    c9=
+
+    cdlog_nicks
+  fi
+}
+
+# Print four recen cdlog entries.
+cdlog()
+{
+  # c5 through c9 are "hidden"
+  printf "c1/x: %s\n" "$c1"
+  printf "c2/y: %s\n" "$c2"
+  printf "c3/z: %s\n" "$c3"
+  printf "c4/w: %s\n" "$c4"
+}
+
+# Aliases.
+alias cs='cdlog_chdir "$c1"'
+alias cd='cdlog_chdir -P'
+alias pd='cdlog_pop'
+
+# Better completion for $x[Tab]
+shopt -s direxpand
+
+# Copyright 2024
+# Kaz Kylheku <kaz@kylheku.com>
+# Vancouver, Canada
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following condition is met:
+#
+# 1. Redistributions of source code must retain the above copyright notice, this
+#    list of conditions and the following disclaimer.
+#
+# 2. Redistributions in binary form need not reproduce any copyright notice.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+# SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+# CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+# OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.