Port lhn() to POSIX sh

3 files changed, 14 insertions, 8 deletions

diff --git a/README.markdown b/README.markdown
index b1e581d5..558c8739 100644
--- a/README.markdown
+++ b/README.markdown
@@ -180,6 +180,8 @@ in `sh/shrc.d` to be loaded by any POSIX interactive shell. Those include:
     information written by the `grep.sh` script in `~/.profile.d`.
 *   `hgrep()` allows searching `$HISTFILE`.
 *   `keychain()` updates `$GPG_TTY` if set for `keychain(1)`.
+*   `lhn()` gets the history number of the last command, if the POSIX `fc`
+    builtin is available.
 *   `ls()` tries to apply color to `ls(1)` for interactive use if available.
     It's dependent on information written by the `ls.sh` script in
     `~/.profile.d`.
@@ -206,7 +208,6 @@ There are a few other little tricks defined for other shells, mostly in
 *   `fnl()` runs a command and saves its output and error into temporary files,
     defining variables with the filenames in them.
 *   `keep()` stores ad-hoc shell functions and variables.
-*   `lhn()` gets the history number of the last command.
 *   `path()` manages the contents of `PATH` conveniently.
 *   `prompt()` sets up my interactive prompt.
 *   `pushd()` adds a default destination of `$HOME` to the `pushd` builtin.
diff --git a/bash/bashrc.d/lhn.bash b/bash/bashrc.d/lhn.bash
deleted file mode 100644
index 89c6f5da..00000000
--- a/bash/bashrc.d/lhn.bash
+++ /dev/null
@@ -1,7 +0,0 @@
-# Print the history number of the last command
-lhn () {
-    local last
-    last=$(fc -l -1) || return
-    [[ -n $last ]] || return
-    printf '%u\n' "${last%%[^0-9]*}"
-}
diff --git a/sh/shrc.d/lhn.sh b/sh/shrc.d/lhn.sh
new file mode 100644
index 00000000..15fced6e
--- /dev/null
+++ b/sh/shrc.d/lhn.sh
@@ -0,0 +1,12 @@
+# Print the history number of the last command
+# "fc" is specified by POSIX, but does not seem to be in dash, so its being
+# included here rather than in e.g. ~/.bashrc.d is a bit tenuous.
+lhn () {
+    if ! command -v fc >/dev/null 2>&1 ; then
+        printf 'lhn(): fc: command not found\n'
+        return 1
+    fi
+    set -- "$(fc -l -1)"
+    [ -n "$1" ] || return
+    printf '%u\n' "$1"
+}