Re: what is /usr/bin/head

When you encounter a unix command and you don't know what it is you can try googling for man head or run "man head" on your unix box.

PS: My experience is to beware of using the unix command line tools on OSX. The cp command does not copy the filesystem meta-data associated with a file. This can make some quicktime video files impossible to play due to removing codec information.

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Re^2: what is /usr/bin/head by jhourcle (Prior) on May 23, 2006 at 13:07 UTC
Actually, that's not true under 10.4 ... well, at least, it copies the resource fork. For earlier versions of MacOS, you'll want to install the developer tools, and set aliases for cp and mv to 'CpMac' and 'MvMac' (and yes, I had some file corruption problems under 10.2, until someone told me what was going on ... empty preferences files for some applications can cause them to lock up in new and interesting ways) Oh -- and MacOS stores a _lot_ of metadata for files. (besides just the resource fork, which will can break some files, there's also indexing information, ACLs, and a bunch of stuff that might not be as noticable) ... there's a table of MacOS backup software that might be useful for whole volumes, but I don't know how useful it is for moving individual files. update: you'll also notice when creating tarballs or moving to non-HFS systems that you'll get two items for every file -- the data fork under the original name, and one prefixed with '`._`', which is the resource fork. (just ran into the problem yesterday, when someone grabbed a power point presentation off a memory stick, and grabbed the wrong fork)	[reply]

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Re^2: what is /usr/bin/head
by jhourcle (Prior) on May 23, 2006 at 13:07 UTC

Actually, that's not true under 10.4 ... well, at least, it copies the resource fork. For earlier versions of MacOS, you'll want to install the developer tools, and set aliases for cp and mv to 'CpMac' and 'MvMac'

(and yes, I had some file corruption problems under 10.2, until someone told me what was going on ... empty preferences files for some applications can cause them to lock up in new and interesting ways)

Oh -- and MacOS stores a _lot_ of metadata for files. (besides just the resource fork, which will can break some files, there's also indexing information, ACLs, and a bunch of stuff that might not be as noticable) ... there's a table of MacOS backup software that might be useful for whole volumes, but I don't know how useful it is for moving individual files.

update: you'll also notice when creating tarballs or moving to non-HFS systems that you'll get two items for every file -- the data fork under the original name, and one prefixed with '._', which is the resource fork. (just ran into the problem yesterday, when someone grabbed a power point presentation off a memory stick, and grabbed the wrong fork)

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