ZIPALIGN(1)

💖 ZIPALIGN(1) 💖

okay bestie, gather round, because today we're reading zipalign — that's section 1 of the manual, and it's the ZIP/APK alignment tool for Android application files. niche? yes. iconic? also yes. let's get into it 🦋

✨ NAME ✨

zipalign — a ZIP/APK alignment tool for Android application files. that's the whole name, short and stunning, no notes 💅

🎀 SYNOPSIS 🎀

so first vibe: you wanna align infile.zip and save it as outfile.zip, right? boom:

zipalign [-f] [-p] [-v] [-z] align infile.zip outfile.zip

and if you're just here to confirm that existing.zip is already aligned, you do this instead:

zipalign -c [-p] [-v] align existing.zip

now the tea on align: it's an integer that defines the byte-alignment boundaries. and listen — it must always be 4 (which gives you 32-bit alignment) or else it effectively does <em>nothing</em>. like, literally nothing. so don't get creative with it, bestie 🙈

🌸 DESCRIPTION 🌸

zipalign is an archive alignment tool, and it provides important optimization to Android application (.apk) files. the whole point is making sure all uncompressed data starts with a particular alignment relative to the start of the file. specifically, it causes all uncompressed data within the .apk — think images, raw files, all of it — to be aligned on 4-byte boundaries. why do we care? because that lets every portion be accessed directly with mmap(), even if it contains binary data with alignment restrictions. and the payoff is a reduction in the amount of RAM consumed when the application is running. it's giving efficiency, it's giving main character energy 👑

you should always use this tool to align your APK file before distributing it to end-users. good news though: the Android build tools can handle this for you, and Android Studio automatically aligns your APK. so like, you're covered ✨

Caution: you must use zipalign at one of two specific points in the app-building process, and which one depends on which app-signing tool you use:

• if you use apksigner, zipalign must only be performed before the APK file has been signed. and fr fr, if you sign your APK using apksigner and then make further changes to the APK, its signature is invalidated. 💀
• if you use jarsigner, zipalign must only be performed after the APK file has been signed.

the adjustment itself is made by altering the size of the “extra” field in the zip Local File Header sections. and heads up: existing data in the “extra” fields may be altered by this process. so don't be surprised 😭

want more info about how to use zipalign when building your application? go read “Signing Your Application”: https://developer.android.com/tools/publishing/app-signing.html

💅 OPTIONS 💅

five flags, all iconic, all useful:

• -c — Check alignment only (does not modify file). a little looky-loo, zero changes.
• -f — Overwrite existing outfile.zip. yes, we're bulldozing the old one.
• -p — Memory page alignment for stored shared object files.
• -v — Verbose output. give me all the details, I wanna know everything.
• -z — Recompress using Zopfli.

🦋 SEE ALSO 🦋

• ZIPTIME(1)
• https://developer.android.com/studio/command-line/zipalign.html

🌈 AUTHORS 🌈

The Android Open Source Project. periodt.

and that's the whole page, bestie 🫶 thanks for reading zipalign(1) with me — that footer saying ZIPALIGN(1) again is just the manual being extra, and honestly? respect the consistency 💜