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dotfiles/config/shell/.config/zsh/conf.d/10-oops.zsh
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2026-07-27 02:53:24 +02:00

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# Remove the last command from history (both memory and file).
#
# NOTE: other shells running concurrently still hold the entry in their own
# in-memory history and can write it back; SHARE_HISTORY does not propagate
# deletions.
uy_oops_confirm() {
# Flush current session to file so we operate on the latest state
fc -W
if [[ ! -f "$HISTFILE" || ! -s "$HISTFILE" ]]; then
print -P "%F{yellow}History is empty, nothing to delete.%f"
return 1
fi
# Find where the last entry starts. An entry continues onto the next line
# when the current one ends in a backslash; zsh writes a command that itself
# ends in a backslash as "\ " (trailing space), so the marker is unambiguous.
# Walking forward and remembering the start of each entry is exact for
# entries of any length.
local start
start=$(awk '{ if (!cont) start = NR; cont = /\\$/ } END { print start + 0 }' "$HISTFILE")
if [[ -z "$start" ]] || (( start < 1 )); then
print -P "%F{yellow}Could not parse last history entry.%f"
return 1
fi
local -a ordered
ordered=("${(@f)$(tail -n +"$start" "$HISTFILE")}")
if (( ${#ordered[@]} == 0 )); then
print -P "%F{yellow}Could not parse last history entry.%f"
return 1
fi
local line
print -P "About to permanently delete the last command from history:"
for line in "${ordered[@]}"; do
print -P " %F{red}${line}%f"
done
local reply
echo -n "Proceed? [Y/n] "
read -r reply
if [[ -z "$reply" || "$reply" == [yY]* ]]; then
# Keep everything before the entry. start-1 == 0 (the entry is the only
# one) correctly leaves an empty file.
local n=${#ordered[@]}
head -n $(( start - 1 )) "$HISTFILE" > "$HISTFILE.tmp" && mv "$HISTFILE.tmp" "$HISTFILE"
# Replace the in-memory history with the updated file. `fc -p` is the
# only primitive that replaces it: `fc -R` *appends* the file on top of
# what is already in memory, which both duplicates every entry and
# leaves the deleted command there for the next `fc -W` to write back.
#
# `fc -p` pushes a history layer, and each layer retains a full copy of
# the history, so pop the layer the previous call left behind first —
# that keeps exactly one live no matter how often `oops` runs. `fc -P`
# only restores the old in-memory list, it does not write to $HISTFILE,
# so it cannot undo the deletion above; and the push on the very next
# line replaces that stale list immediately. Both must stay in this
# branch: on the cancel path nothing was deleted, so memory already
# matches the file and popping would corrupt it.
fc -P 2>/dev/null
fc -p "$HISTFILE" $HISTSIZE $SAVEHIST
print -P "%F{green}Deleted ($n line(s) removed).%f"
else
# Nothing was modified, so there is nothing to reload.
print -P "%F{yellow}Cancelled.%f"
fi
}
# The alias has a leading space so "oops" itself is not recorded (HIST_IGNORE_SPACE).
alias oops=' uy_oops_confirm'