Arcmc

arcmc archive browser

Русская версия

arcmc is a panel plugin for browsing, creating, testing and extracting archives. It uses libarchive for the formats libarchive understands and can delegate other formats to command-line programs through extfs helpers.

Everyday use

• Press Ctrl+PgDn on an archive to open it in an arcmc panel.
• Press Enter on the common built-in archive formats. Their Open associations are supplied by the system magic.ini.
• Press F3 on a common archive to view its catalogue as text.
• Inside an arcmc panel, use Enter to descend into directories or nested archives. A regular non-archive file is sent to the viewer.
• Standard panel copy and delete operations work inside the archive when the selected backend supports them.
• The plugin menu contains Open archive, Create archive, Extract archive(s), Test archive(s) and Archiver settings.
• Shift+F1 creates an archive from the current or tagged entries by default. The key is configurable.

Long operations show progress, throughput and estimated time and can be cancelled. Extraction rejects absolute paths and .. path components, so an archive entry cannot escape the selected destination.

How opening an archive works

sequenceDiagram
    actor User
    participant Panel as File panel
    participant Magic as magic.ini
    participant Plugins as Plugin registry
    participant Arcmc as arcmc

    User->>Panel: Enter or Ctrl+PgDn
    alt Enter
        Panel->>Magic: Find Open rule
        Magic-->>Panel: arcmc:open
    else Ctrl+PgDn
        Panel->>Magic: Find explicit rule
        alt arcmc rule exists
            Magic-->>Panel: arcmc:open
        else No rule
            Panel->>Plugins: Try Open operations by filename
            Plugins-->>Panel: arcmc:open
        end
    end
    Panel->>Arcmc: Open file or stream
    alt Archive accepted
        Arcmc-->>Panel: Activate archive panel
    else Not an archive
        Arcmc-->>Panel: Not supported
    end

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Ctrl+PgDn can therefore use a suffix added to arcmc.ini at runtime; adding another format does not require rebuilding mc or generating a system magic.ini rule. Enter remains controlled by magic.ini, so adding a custom suffix does not unexpectedly change the normal Enter action.

Built-in and external formats

libarchive handles ZIP, 7z, TAR variants and CPIO for reading and writing. It also reads formats such as ISO, XAR and CAB. ZIP aliases include JAR, WAR and EAR. The exact availability depends on the libarchive build.

The external registry includes defaults for RAR, ARJ, ACE, ARC, ALZ, ZOO, HA, WIM, LHA/LZH, DEB, RPM and Inno Setup installers. These entries describe external programs and helpers; the corresponding tools still have to be installed. The Archiver settings dialog shows built-in and external formats, lets you enable or disable them, selects built-in/external backends where both exist, and marks a missing tool with !.

Configuration files

The plugin stores its settings in the Midnight Commander user configuration directory, normally:

${XDG_CONFIG_HOME:-$HOME/.config}/mc6/arcmc.ini

The user magic.ini, when needed, is in the same directory. The two files have different jobs:

• arcmc.ini defines archive formats, programs, helper names and enabled state.
• magic.ini chooses which action invokes a handler for Enter, F3 or an explicit Ctrl+PgDn association.

Restart mc after editing arcmc.ini; the external registry is loaded when the plugin is registered.

The create-archive shortcut is stored separately from format definitions:

[arcmc]
hotkey_create=shift-f1

Use none to disable the shortcut.

Adding an external format without recompiling

The following example registers .foo:

[arcmc-ext]
FOO=true

[arcmc-ext-params-FOO]
extension=.foo
pack_bin=foo-archive
pack_args=create
unpack_bin=foo-archive
unpack_args=extract
test_bin=foo-archive
test_args=test
extfs_helper=ufoo
list_file_arg=@%s

FOO is an arbitrary case-insensitive name. Unknown formats must define extension; the leading dot is optional. Names cannot contain =, [ or ], control characters, or leading/trailing whitespace. mc writes names back in canonical uppercase form.

Suffix matching is case-insensitive. If suffixes overlap, the longest suffix wins. A missing key in [arcmc-ext] means enabled. An enabled suffix is offered to Ctrl+PgDn only when at least one configured binary is in PATH; an entry that names only an extfs helper is accepted as helper-only.

Key	Purpose
extension	Filename suffix. ext is accepted as a compatibility alias.
pack_bin	Program used to create or update an archive.
pack_args	Arguments after pack_bin and before the archive name.
unpack_bin	Program used for bulk or selective extraction.
unpack_args	Arguments after unpack_bin and before the archive name.
test_bin	Program used by Test archive(s).
test_args	Arguments after test_bin and before the archive name.
extfs_helper	Helper used to list the archive and access individual entries.
list_file_arg	printf-style file-list argument, for example @%s, used when a command would exceed 128 KiB.

Missing command keys disable the corresponding operation. An empty value clears a built-in default. The *_args values are trusted shell command fragments, not argument arrays or placeholder templates. Commands are formed as follows:

pack_bin pack_args archive files...
unpack_bin unpack_args archive [destination]
test_bin test_args archive

For selective extraction, arcmc changes to the destination directory and runs unpack_bin unpack_args archive files....

How extfs helpers relate to arcmc

The helpers shipped in src/vfs/extfs/helpers/ implement the extfs command protocol. arcmc reuses this protocol as an adapter for external archivers. It executes the helper directly and does not open or mount an extfs VFS path such as archive/uzip://.

flowchart LR
    A[arcmc panel] -->|list| B[extfs helper]
    A -->|view or copy| C[copyout]
    A -->|add| D[copyin]
    A -->|delete| E[rm]
    B --> F[External archive tool]
    C --> F
    D --> F
    E --> F

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For extfs_helper=ufoo, arcmc searches for an executable ufoo in this order:

1. ${XDG_DATA_HOME:-$HOME/.local/share}/mc6/extfs.d/
2. the system extfs.d directory below mc's configured library-executable directory, commonly /usr/libexec/mc/extfs.d/

The helper interface used by arcmc is:

ufoo list archive.foo
ufoo copyout archive.foo path/inside/archive destination
ufoo copyin archive.foo path/inside/archive source
ufoo rm archive.foo path/inside/archive

list is required for browsing a format libarchive cannot read, and its output must use the modified ls -l format from the extfs helper documentation. copyout is required to view or copy files. copyin and rm are optional and enable adding and deleting entries.

Install a user helper as an executable file:

install -Dm755 ufoo "${XDG_DATA_HOME:-$HOME/.local/share}/mc6/extfs.d/ufoo"

An external helper needs a local filesystem path for the archive. It cannot browse an archive supplied only as a non-local stream by another panel plugin. If the source plugin can provide a local copy, arcmc can use that copy.

Making Enter open a custom suffix

No magic.ini rule is required for Ctrl+PgDn. To make Enter open .foo with arcmc too, add this user rule:

[arcmc.foo]
Regex=\\.foo$
RegexIgnoreCase=true
Open=%plugin{arcmc:open}

Keep the rule out if Enter should continue using the viewer or another handler.

Inno Setup installers

Inno Setup support is registered by default and is equivalent to:

[arcmc-ext]
INO=true

[arcmc-ext-params-INO]
extension=.exe
test_bin=innoextract
test_args=--test --silent
extfs_helper=uinno

The installed uinno helper uses innoextract for list and copyout, so innoextract must be available in PATH. Stand on an installer and press Ctrl+PgDn. A non-Inno .exe is rejected quietly and remains a normal file; Enter is not reassigned for .exe.

Troubleshooting

• Confirm that the arcmc panel plugin is enabled and restart mc after changing arcmc.ini.
• Check external binaries with command -v program-name.
• Check that a user helper is executable and in the correct extfs.d directory.
• Run ufoo list archive.foo in a shell. A nonzero exit status or malformed listing means arcmc cannot build the panel.
• Use Ctrl+PgDn for a runtime-added suffix. Enter needs the separate magic.ini rule shown above.
• If browsing works but adding or deleting does not, the helper probably lacks copyin or rm; those commands are optional.