Inspect ZIP Archives Safely with zipinfo

You will be able to inspect a ZIP archive's contents, identify useful metadata, select members by name, and produce script-friendly output without extracting anything. The examples use Info-ZIP ZipInfo 3.00 from the Ubuntu unzip package 6.0-28ubuntu4.1. Allow about 10 minutes if the archive is already on the machine.

Before you start

You need a shell and a readable ZIP archive. No root access is needed, and the commands in this guide do not modify the archive or the files around it. Replace /path/to/archive.zip with a real path. Keep the path quoted when it contains spaces or shell wildcard characters.

Check which program is installed and its version:

command -v zipinfo
zipinfo -h

The installed program is also available through unzip -Z. That is useful on a system where the separate zipinfo command is not present.

Checkpoint 1: list the archive

Start with the default listing. It shows one line per archive member, with a header and a totals line.

zipinfo "/path/to/archive.zip"

A typical entry looks like this:

-rw-r--r--  3.0 unx       18 tx stor 26-Sep-28 15:47 demo/run.sh

The leading fields describe permissions, the version of the creating program, the originating file system, uncompressed size, a text or binary hint, extra-field or local-header markers, and the compression method. The date and member name come last. A directory is normally shown as a name ending in /.

The header reports the archive size and entry count. The totals line reports uncompressed and compressed data sizes. Those data totals are not the same as the archive's on-disk size because ZIP headers and other archive structures are included in the latter.

Checkpoint 2: choose the amount of detail

Use -1 when another command needs only member names. It deliberately removes headers, totals and comments.

zipinfo -1 "/path/to/archive.zip"

Use -l for a long listing that adds each member's compressed size. Use -m instead when a compression percentage is more useful.

zipinfo -l "/path/to/archive.zip"
zipinfo -m "/path/to/archive.zip"

Use -v for archive diagnostics, including central-directory details, comments and extra fields. It can be lengthy, so send it to a normal pager:

zipinfo -v "/path/to/archive.zip" | less

The built-in -M pager also works, but the manpage documents limitations with wrapped lines and screen size. A normal pager gives you familiar searching and quitting behaviour.

Checkpoint 3: inspect selected members

Put member names after the archive path to limit the listing. This is useful for checking a single configuration file or a small group of files.

zipinfo -m "/path/to/archive.zip" "config/app.conf"
zipinfo -mt "/path/to/archive.zip" "docs/*.md"

Quote the member pattern. The shell must not expand it against directories on the host machine. In the second command, -t adds totals for the selected members. Supplying member names normally suppresses the archive header and totals unless you request them explicitly.

To exclude members, add -x followed by the unwanted names or patterns:

zipinfo "/path/to/archive.zip" -x "node_modules/*" "*.cache"

Patterns are matched against names stored in the archive, not paths on your file system. If a pattern matches nothing, check the exact spelling with zipinfo -1. ZIP member names are case-sensitive in practice, and a stored directory prefix such as project/ is part of the name.

Dates, comments and machine-readable names

Add -T to print member times as yymmdd.hhmmss. That makes simple sorting more reliable than sorting human-readable month names.

zipinfo -T "/path/to/archive.zip" | sort -nr -k 7

This uses the default short format, where the timestamp begins in field 7. If you use -m or -l, the timestamp moves to field 8. Treat this as a quick inspection pipeline rather than a stable interchange format: filenames containing unusual whitespace can still make field-based parsing unsuitable.

Use -z when you need the archive comment. Use -h for the header and -t for totals. A common trap is that -h or -t on its own asks for only that line, rather than adding it to a full listing. Add a format option when you want members as well:

zipinfo -st "/path/to/archive.zip"
zipinfo -lht "/path/to/archive.zip"

Defaults that can surprise you

On Unix, ZIPINFO and the compatibility variable ZIPINFOOPT can add options to every invocation. An explicit command-line option has higher priority, but an inherited environment setting can still explain missing headers, totals or member lines.

env | grep -E '^(ZIPINFO|ZIPINFOOPT)='
env -u ZIPINFO -u ZIPINFOOPT zipinfo "/path/to/archive.zip"

Use the second command as a clean comparison when output looks wrong. Avoid placing a permanent preference in a shell profile until you understand its effect. In particular, a negated option such as --t disables the default totals line, and a command containing only -t can then print just totals.

Safety and failure checks

zipinfo reads archive metadata. It does not extract members, so these examples do not overwrite files. Do not treat a listing as proof that extraction is safe: archive names can contain absolute paths, parent-directory components or misleading names. If you later extract an untrusted archive, inspect its names first and use a dedicated directory, with extraction-specific safeguards.

For a missing or unreadable archive, check the path and permissions:

test -r "/path/to/archive.zip" && zipinfo "/path/to/archive.zip"
printf 'exit status: %s\n' "$?"

A non-zero exit status means the inspection did not complete successfully. Do not silence it with a pipe that hides the first command's status. For a damaged or incomplete ZIP, the diagnostic from zipinfo is more useful than a partial listing. Re-copy the archive from a trusted source and compare a checksum if integrity matters.

Done means

• You can list names with zipinfo -1 without extracting the archive.
• You can choose short, medium, long or verbose metadata with -s, -m, -l or -v.
• You quote member patterns and understand that filters match stored archive names.
• You know that member filters change the default header and totals behaviour.
• You have checked for ZIPINFO and ZIPINFOOPT when output is unexpected.