apptainer(1)

🎀 apptainer(1) 🎀

Hiii bestie 💖 so you opened the apptainer(1) manual page and honestly? You're in the right place. This one's a little sub-page of the big Apptainer family — it's literally the apptainer-sign page, and it's about making your SIF images officially signed ✨. Let's get into it, no cap.

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✨ SYNOPSIS ✨

apptainer sign [sign options...]

That's the whole vibe. apptainer sign plus whatever options your heart desires 🫶

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💅 DESCRIPTION 💅

Okay so listen — the sign command lets a user add one or more digital signatures to a SIF image. Iconic behavior, honestly. And by default, one digital signature is added for each object group in the file. One per object group, periodt. 💀

Where does the key material come from, you ask? Two ways, bestie:

• A PEM-encoded file 📄
• An entity in the PGP keyring 🔑

And real talk — to manage that PGP keyring, you go see apptainer help key. That's your girl for keyring stuff. iykyk.

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🌸 OPTIONS 🌸

Okay this is the part where we go through every single flag, because we don't skip. Not ever. 💜

• -g, --group-id=0 — sign objects with the specified group ID 🎯
• -h, --help[=false] — the help for sign. Say hi, get help, love that for you 💖
• --key="" — path to the private key file. (Note the default: "", empty string, as in "no path given yet, bestie") 🔑
• -k, --keyidx=0 — which PGP private key to use, given as an index from key list --secret 👑
• -i, --sif-id=0 — sign the object with the specified ID 🦋

Default value on all those numbered ones is 0, just so we're clear. Zero. Not a guess, that's literally what's written. ⭐

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🔥 EXAMPLE 🔥

Two whole examples, both gorgeous:

Sign with a private key:

$ apptainer sign --key private.pem container.sif

Sign with PGP:

$ apptainer sign container.sif

See how the PGP one needs literally no flags? That's because it hits the PGP keyring by default. Main character energy, honestly. 💅

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🧚 SEE ALSO 🧚

• apptainer(1) — the parent page, go say hi to her too 🌈

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🍓 HISTORY 🍓

• 22-Oct-2026 — Auto generated by spf13/cobra 🤖 (not a human, not me, a robot. Respectfully.)

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And that's the page, bestie!! 🎀 This apptainer(1) manual was Auto generated by spf13/cobra, dated Oct 2026, and this whole listing is apptainer(1) at heart. Go sign something iconic with it 💖✨👑