Command Line – Debian Goodies

Many users of Debian or its derivatives are aware of only a handful of tools. When troubleshooting or searching for a package to install, most rely on the Debian web pages for each package. The more expert may use apt-cache. However, these tools give limited information. For more demanding needs, a better alternative is Debian Goodies [1], a collection of small scripts that allow users to probe the details of packages without going through them file by file. First written and curated by Matt Zimmerman, Debian Goodies remain little known but can be equally useful for the casual user looking for a package, a sys admin troubleshooting packages, or a maintainer building a package. Perhaps their strongest feature is that, unlike the package web pages, Debian Goodies deliver results directly to the command line, without the need to switch windows.

dgrep and dglob

Searches can be useful for many purposes when you are troubleshooting packages. For instance, they can find what a package does, what the current package version is, or what programming language a package is written in. If all else fails, they can provide the name of the maintainer so that you can contact them. Both dgrep and dglob are in effect minor add-ons to already existing search tools, each of which deserves its own article. Here, there is only room for a general orientation.

By invoking the basic grep command, dgrep (Figure 1) searches for strings and regular expressions through installed packages. Similarly, degrep invokes egrep, dfgrep invokes fgrep, and dzgrep invokes zgrep. You can limit the search by specifying the packages to search within. The available options are the same as for grep, except for those specific to directories (-r, --recursive, -d recurse, --directories=recurse, -d read, --directories=read) because dgrep skips directories. In addition, symbolic links are not searched.

Figure 1: dgrep searches packages for key strings.

Providing a slightly different approach to searches than dgrep, dglob (Figure 2) searches installed package names by default. However, adding the -a search broadens a search to include all available packages and omits package architectures if -A is added as well. By contrast, -n omits installed packages from the search. In addition, -f lists all the files in matched packages. The use of both -a and -n can be further refined by the options for grep-dctrl(1) and grep-aptavail(1). Similarly, -f can be used with aptfile's options.

Figure 2: Like dgrep, dglob searches packages.

Searches with dglob can also be modified with:

• --regex (-rv): Treats the entire search string as a regular expression
• --ignore-case (-i): Treats uppercase and lowercase letters the same
• --exact-match (-X): Gives only exact matches in results
• --invert-match (-v): Shows only results that do not match the search string

If these options are not enough, check the man pages of the commands that dgrep and dglob invoke.

debget

Primarily for developers rather than users, debget (Figure 3) lets developers download a package for study and development into their present working directory. A particular version of a package can be downloaded by adding =VERSION to the end of the package name.

Figure 3: With debget, you can download a package to a local directory.

dpigs

Similar to the top command, dpigs (Figure 4) lists the packages that take up the most space (instead of listing running applications). Like top, dpigs lists the largest memory hogs first. You can limit the number of items displayed with --lines=NUMBER (-n=NUMBER). Instead of package names, it can list package files with --status=FILES (-s=FILES). More detailed information about files can be displayed with --human-readable (-H).

Figure 4: Just as top shows the largest active processes, dpigs shows the packages that take up the most diskspace.