Write to a temp file in the SAME directory, then `mv` to the final name. mv on the same filesystem is atomic — readers never see a half-written file.
Bash
atomic_write() {
local target="$1" content="$2"
local dir
dir="$(dirname "$target")"
local tmp
tmp="$(mktemp "$dir/.$(basename "$target").XXXXXX")"
printf '%s' "$content" > "$tmp"
mv "$tmp" "$target" # atomic on POSIX, same filesystem
}
# Usage
atomic_write /var/lib/myapp/state.json '{"ready": true}'
# Concurrent-safe pattern for cron jobs writing the same file:
update_status() {
local out="/var/lib/myapp/status.txt"
atomic_write "$out" "Last run: $(date -u +%FT%TZ)"
}Save your own code snippets
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