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For the record as this thread is quite old.

7-zip does not allow streamed write of 7z format, it requires free seeking access as it writes, amongst the other stuff, header at the end of operation. It does allow to pipe standard *nix formats like bz2, gz, xz, though. It also allows to pipe single input without restrictions (-si switch).

So one can compress single file into 7z format but cannot pipe it further.

$ cat archive.tar | 7z a -si archive.tar.7z 

Other formats, like mentioned bz2, gz, xz can be written to stdout (-so switch).

$ cat archive.tar | 7z a -tgzip -si -so -an > archive.tar.gz == $ 7z a -si -so -tgzip -an < archive.tar > archive.tar.gz 

This obviously allows to pipe it further:

$ cat archive.tar | 7z a -tgzip -si -so -an | wc -c 

Note -an switch that disables parsing of archive_name. What it actually does, god one knows - this program is bit magical and you have to cope with its quirks. Example of this behaviour can be found here.

For the record as this thread is quite old.

7-zip does not allow streamed write of 7z format, it requires free seeking access as it writes, amongst the other stuff, header at the end of operation. It does allow to pipe standard *nix formats like bz2, gz, xz, though. It also allows to pipe single input without restrictions (with -si switch).

So one can compress single file into 7z format but cannot pipe it further.

$ cat archive.tar | 7z a -si archive.tar.7z 

Other formats, like mentioned bz2, gz, xz can be written to stdout (with -so switch).

$ cat archive.tar | 7z a -tgzip -si -so -an > archive.tar.gz == $ 7z a -si -so -tgzip -an < archive.tar > archive.tar.gz 

This obviously allows to pipe it further:

$ cat archive.tar | 7z a -tgzip -si -so -an | wc -c 

Note -an switch that disables parsing of archive_name. What it actually does, god one knows - this program is bit magical and you have to cope with its quirks. Example of this behaviour can be found here.

For the record as this thread is quite old.

7-zip does not allow streamed write of 7z format, it requires free seeking access as it writes, amongst the other stuff, header at the end of operation. I does allow to pipe standard *nix formats like bz2, gz, xz, though. It also allows to pipe single input without restrictions (-si switch).

So one can compress single file into 7z format but cannot pipe it further.

$ cat archive.tar | 7z a -si archive.tar.7z 

Other formats, like mentioned bz2, gz, xz can be written to stdout (-so switch).

$ cat archive.tar | 7z a -tgzip -si -so -an > archive.tar.gz == $ 7z a -si -so -tgzip -an < archive.tar > archive.tar.gz 

This obviously allows to pipe it further:

$ cat archive.tar | 7z a -tgzip -si -so -an | wc -c 

Note -an switch that disables parsing of archive_name. What it actually does, god one knows - this program is bit magical and you have to cope with its quirks. Example of this behaviour can be found here.

For the record as this thread is quite old.

7-zip does not allow streamed write of 7z format, it requires free seeking access as it writes, amongst the other stuff, header at the end of operation. It does allow to pipe standard *nix formats like bz2, gz, xz, though. It also allows to pipe single input without restrictions (-si switch).

So one can compress single file into 7z format but cannot pipe it further.

$ cat archive.tar | 7z a -si archive.tar.7z 

Other formats, like mentioned bz2, gz, xz can be written to stdout (-so switch).

$ cat archive.tar | 7z a -tgzip -si -so -an > archive.tar.gz == $ 7z a -si -so -tgzip -an < archive.tar > archive.tar.gz 

This obviously allows to pipe it further:

$ cat archive.tar | 7z a -tgzip -si -so -an | wc -c 

Note -an switch that disables parsing of archive_name. What it actually does, god one knows - this program is bit magical and you have to cope with its quirks. Example of this behaviour can be found here.

For the record as this thread is quite old.

7-zip does not allow streamed write of 7z format, it requires free seeking access as it writes, amongst the other stuff, header at the end of operation. I does allow to pipe stand though standard *nix formats like bz2, gz, xz. It also allow to pipe single input without restrictions (-si switch).

So one can compress single file into 7z format but cannot pipe it further.

$ cat archive.tar | 7z a -si archive.tar.7z 

Other formats, like mentioned bz2, gz, xz can be written to stdout (-so switch).

$ cat archive.tar | 7z a -tgzip -si -so -an > archive.tar.gz == $ 7z a -si -so -tgzip -an < archive.tar > archive.tar.gz 

This obviously allows to pipe it further:

$ cat archive.tar | 7z a -tgzip -si -so -an | wc -c 

Note -an switch that disables parsing of archive_name. What it actually does, god one knows - this program is bit magical and you have to cope with its quirks. Example of this behaviour can be found here.

For the record as this thread is quite old.

7-zip does not allow streamed write of 7z format, it requires free seeking access as it writes, amongst the other stuff, header at the end of operation. I does allow to pipe standard *nix formats like bz2, gz, xz, though. It also allows to pipe single input without restrictions (-si switch).

So one can compress single file into 7z format but cannot pipe it further.

$ cat archive.tar | 7z a -si archive.tar.7z 

Other formats, like mentioned bz2, gz, xz can be written to stdout (-so switch).

$ cat archive.tar | 7z a -tgzip -si -so -an > archive.tar.gz == $ 7z a -si -so -tgzip -an < archive.tar > archive.tar.gz 

This obviously allows to pipe it further:

$ cat archive.tar | 7z a -tgzip -si -so -an | wc -c 

Note -an switch that disables parsing of archive_name. What it actually does, god one knows - this program is bit magical and you have to cope with its quirks. Example of this behaviour can be found here.