SwissArmy Knives

If you work on the command line, you inevitably use many utilities and tools, all of which work differently, especially if you have to switch between operating systems. To simplify your life, take a look at Swiss File Knife (SFK) [1]: This tool replaces many conventional command-line programs with functions that operate consistently and follow the same syntax across operating systems. Additionally, SFK offers a way to combine individual commands in scripts. A short overview of the tool's many options is given in the "Swiss File Knife Capabilities" box.

SFK is available as a precompiled program with no dependencies, so you can take it anywhere you like on a USB stick and use it for on-site maintenance or rescue work. In addition to 32- and 64-bit binaries for Linux, you will find versions for the Raspberry Pi and other ARM machines, as well as Windows and Mac OS X, allowing you to work on all the major systems with the same tool.

Choosing your Weapons

All versions of SFK can be found on the tool's SourceForge page [2] below Files | 1-swissfileknife | <version> (v1.7.2 when this issue went to press). In the list, then click on the EXE file for your system, which you can identify by looking at the file name.

For the Raspberry Pi and other ARM computers, you will need ...-arm.exe, whereas ...-linux.exe and -linux-64.exe are available for 32- and 64-bit Linux versions.

The file with the -linux-lib5 suffix is intended for older distributions that still use the libstdc++.so.5 library. The OS X versions for PPC and Intel machines are identified by the mac name component. The Windows version is simply called sfk<version>.exe.

A ZIP archive is available for download that contains, among other things, the Mac OS X, Windows, and Linux (32-bit) versions. After unpacking, you will find the Linux programs in the uxbin subdirectory.

Don't let the .exe suffix throw you with the Linux and Mac versions: It is still an executable binary. You can rename it to sfk (no extension) and make it executable with:

chmod +x sfk

You can then use SFK directly, without having to install it. For computers on which you want to use SFK regularly, it makes sense to copy it to a suitable location such as ~/bin or /usr/bin.

In addition to the free version of Swiss File Knife under the BSD license, StahlWorks Technologies also offers a commercial "Extended Edition" [3] that lets you additionally search and filter the contents of .zip, .tar.gz, and .tar.bz2 archives and replace strings and byte sequences rapidly in text or binary files.

Moreover, the tool understands wildcards and special search patterns for find and replace actions (but still no regular expressions). The Extended Edition is only available as a 32-bit program and is not available at all for ARM machines; a license costs EUR30 (~$35).

Tricky

If you call SFK without any parameters, it presents you with its feature list. Options tell the program which task you need it to complete. For example, sfk list Music lists all the files in the Music subdirectory (Figure 1).

Figure 1: Initially, sfk simply lists all the files in the Music directory; the next command sorts them by their last modification time; finally, the command outputs the three most recently modified files.

The first parameter basically always determines the action to perform. For example, list tells SFK to output a list of files. The developers of Swiss File Knife refer to these functions as commands. The second parameter references the directory or file to which the command refers.

Following this pattern, you can call other functions in a similar way. Some commands can be fine-tuned using other parameters. For example,

$ sfk list -late=all Music

lists all the files from the Music directory sorted by date and time stamps. If you replace all with the number 3, then SFK displays only the first three files.

If you specify parameters, they must follow the command name immediately. Just calling sfk list will give you a list of all parameters. Calling most of the other commands without parameters also provides detailed information about the options. For example, typing sfk ftp reveals how you can upload a file to an FTP server.

No Rules Without Exceptions

Some commands do not require parameters and get to work immediately. For example, sfk space reveals how much free space is available on the current drive. For these commands, the -help parameter returns a help page (Figure 2). To discover which commands do this, you again need to type sfk: Swiss File Knife marks these commands, usually with the abbreviation [-h].

Figure 2: The online help for the space command is unusually short. Other commands can output several screens of information.

Output from SFK help pages is typically quite long. To consume the information thoughtfully, it makes sense to redirect the output to a text file:

$ sfk list > list_help.txt

It is a bit easier to search the reference on the SFK site at [1]. StahlWorks Technologies also sells a $2.95 PDF with a reference for all commands [4]. The first 20 pages can be read for free. Essentially, this is just the contents of the help pages that SFK outputs, so you can save yourself the expense of this purchase.