7 Zip Split Files

[Elwanda Menhennett]

Orwhat's the best way to split it? Can I use 7-Zip to create separate volumes and then unzip one of them separately? Will it be readable or does it need all the other parts to unzip into the big file again?

I put together a quick 48-lines Python script that splits the large file into 0.5 GB files which are easy to open even in Vim. I've just needed to look through data towards the last part of the log (yes, it is a log file). Each record is split across multiple lines so grep would not do.

In any case, for opening large text files, may I recommend EmEditor. They claim themselves it can open very large files (up to cca. 250 GB), and I've used it in the past for files up to 2 GB. But in any case, I think it may be a better solution than splitting.

Check out Large Text File Viewer, it's great for things like this. Most archivers and splitters will separate the file into pieces which cannot be used to read each piece of data independently and properly, you need to extract them all to get the file back.

You can use 7-Zip itself to split the files. (You can save as a .zip or .7z format.) When you go to create the archive there is an option called "Split volume, bytes". Just select how large you want the chunks.

Works great for me. And splits files respecting lines which is what I was looking for. It also says it's all HTML5 client side so it's safe to use. I'm not sure how big it can go but I think it depends on your machine's ram.

The Large Text Viewer App can be installed on Windows through the Microsoft Store and it offers an option to cut the file in chunks of size.It may well be that it uses the same editor previously mentioned (behind the scenes), but the option to install it from a known source is better IMHO than the alternative links offered.It worked great for me.

I have found the program ffsj very useful. There doesn't seem to be a homepage around currently. But there is a download page here. Be careful with the download clicks, as they try to get you to download additional software, as well.

In Total Commander, highlight the file you want to split. Select [file][split file] from the menu. In the pop-up, select your target-directory and "bytes per file".Choose from: 1.44 MB, 1.2 MB, 720 K, 360 K, 100 MB, 250 MB, 650 MB or 700 MB.Press OK and watch the magic happen...

Tracks: Export each audio track in your project to a separate file. File names are based on the track names. Any labels in the project are ignored.

Labels: Choose this option if your project contains labels as well as one or more audio tracks.

Only labels in the uppermost label track are used for export. > If more than one audio track is above the uppermost label track, the audio of all those tracks will be mixed into the exported files, unless you press the Mute button on some of the tracks to exclude them from the mix.

The label track must contain at least one point or region label, thus:

After you select pages and set up separator lines, click Save. Acrobat saves the split PDFs in an Adobe cloud storage folder within your Acrobat account. You can rename, download, or share the new PDFs with others.

If you need to do more with PDFs beyond splitting files, you can try Adobe Acrobat Pro for Mac or Windows for free for seven days. The Acrobat PDF editor tools let you edit PDFs, merge PDFs, reorder individual pages, extract pages, delete pages, rotate PDF pages, reduce file size, set passwords and permissions, and add bookmarks. You can also convert images like PNGs or JPGs and convert PDFs to and from Microsoft Word, PowerPoint (PPT), and Excel.

I have been using --split-files when using fastq-dump, but I have seen a lot of posts saying to use --split-3. The manual page is not quite clear about the difference between the two commands (besides the number of files generated), so could someone tell me what the difference is between the two commands, and under what circumstances it may be better to use one over the other?

"--split-3 will output 1,2, or 3 files: 1 file means the data is not paired. 2 files means paired data with no low quality reads or reads shorter than 20bp. 3 files means paired data, but asymmetric quality or trimming. in the case of 3 file output, most people ignore .fastq . this is a very old formatting option introduced for phase1 of 1000genomes. before there were many analysis or trimming utilities and SRA submissions always contained all reads from sequencer. back then nobody wanted to throw anything away. you might want to use --split-files instead. that will give only 2 files for paired-end data. or not bother with text output and access the data directly using sra ngs apis." (from Question: fastq-dump split-3 output )

Hi, as I stated in my question I don't think it is clearly explained because the explanation for --split-files makes it sound as if a separate file will be created for each read, which isn't correct as it just splits them into two files. Based on that, I don't really understand why you would use --split-3 vs --split-files to get the same result.

"fastq-dump" is used with Illumina data and traditionally "read" data in Illumina speak refers to Read 1 or Read 2 (not individual reads in the files, which if you think about logically would not make sense i.e. a separate file for each read).

I have a Canon Vixia HF R800. The memory card in it is formatted as exFAT, which supports file sizes greater than 4 GB. However, I shot a continuous video about an hour long, and the camera stored the video on the memoy card as 4 individual files, 3 of them a hair over 4 GB, and the last one a bit under 4 GB. Why is this happening? The memory card should support one large file. I can't find any camera setting that specifies the maximum file size, or anything like that.

Hello jla930,

The camera has the ability to capture files that are 4GB in size or 29m 59s in length, whichever comes first. It does not record clips continuously like a tape would, it breaks them up into 4GB clips. These are able to be merged seamlessly during the post-production process.

This, unfortunately, is the limitation of the FAT file system used on so many cameras. DLSRs have a limitation of 30mins max in HD but not in 4k. For long recordings you should possibly look at using an external recorder which has no file size or time limitations. There is the Blackmagic Video Assist and also the Atomos range which can take a clean HDMI feed from the camera.

Thank you for the reply. I understand that the File system has to split and roll over to the next file, no issues there if my one hour recording is 2 files or 10 files. But the Camera CPU and Hardware should have enough buffering to prevent data loss as the CCD images and Audio are still streaming in real time. Yes I thought of another box to record, but sort of defeats the purpose of the camcorder!! We are a small church on a limited budget, I think canon is out. I'm now looking at a Sony CX550V do you know anything about that?

Replace filename with the name of the large file you want to split. Replace prefix with the name you want to give the small output files. You can exclude [options], or replace it with either of the following:

If you use the -l (a lowercase L) option, replace linenumber with the number of lines you'd like in each of the smaller files (the default is 1,000). If you use the -b option, replace bytes with the number of bytes you'd like in each of the smaller files.

The split command will give each output file it creates the name prefix with an extension tacked to the end that indicates its order. By default, the split command adds aa to the first output file, proceeding through the alphabet to zz for subsequent files. If you do not specify a prefix, most systems use x.

will produce three files, with the first being the index file (you don't need that), the second one the UMI+CB and the third one the cDNA read. I would include --gzip to compress the files right away. Usually I would also use prefetch to download the sra file first and then run fastq-dump on that file for the conversion as the latter tool is notoriously unstable and unreliable, hence running on the downloaded file is usually a bit more robust. Typically I recommend visiting sra-explorer.info to get fastq download links directly but recently it seems to be non-functional, maybe due to changes in the ENA API that it queries for download links, at least it does not return anything in my hands so using prefetch+fastq-dump is the choice I guess.

If you prefetch first then it is fastq-dump (...) SRR19687957.sra on the downloaded file. Otherwise it makes no sense. Why fasterq again, I think it was demonstrated here compellingly that this is no choice.

Yeah, another brick in the wall why fasterq-dumb (b is not a typo) is even worse than the original version, unable to perform basic operations and not providing gzip compression options. Absolutely terrible, like the enrire SRA framework. This entire sra2fastq conversion thing is one of the top unnecessary wastes of computation resources.

You should add surfix .sra to the downloaded file. Otherwise, it will automatically download the data from SRA no matter you have downloaded it or not. The output directory need to be a different path to be distinguished from the directory which contains your downloaded .sra files. I tested many times to make fastq-dump/fasterq-dump work, it always report error when I stored the sra files with splited fastqs.

side note: coworker's command was fasterq-dump --split-files SRR19687957.sra -- gzip which he said it still gave output as one read file. He tried it with a completely different accession number which he got 2 running the same command, but he said for some reason this one that Im working on only gave out one.

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