Tool tests on the fast track


Powerful Ping alternative
License: GPL
Alternatives: Ping

Fping sends ICMP packets to a computer and evaluates the response times. Because the tool relies on raw sockets, it requires root privileges. If you want IPv6 support, you need to enable this when compiling the source code. The executable is then named fping6 rather than fping.

Unlike legacy Ping, the Fping can ping several systems at the same time, either by typing the addresses in manually or by passing them in as a file with the -f parameter. To test all computers on a subnet, -g expects the network address and subnet mask as options. A combination of -a and -q tells Fping to show you only the accessible systems and hide the error messages from unreachable hosts.

Just like Ping, Fping sends 56-byte data packets. The -b optin tells the program to reduce packet size to 12 bytes or increase it to 64KB. If you prefer to see the name of the target computer instead of the IP addresses in the output, you can enable DNS lookup with -d.

Fping does not wait for a response or a timeout after sending an ICMP packet; rather, it uses a round-robin approach and moves directly to the next host. Once the tool has received a response, it removes the host from the list and generates output. By default, it tries to reach a system three times, but -r lets you increase the number of attempts. The -l parameter enables an infinite loop; -s shows a statistical evaluation.

Fping not only pings multiple hosts simultaneously, it outputs extra details.

LNAV 0.5.0

Logfile Navigator
License: BSD revised
Alternatives: MultiTail

If you need to check logfiles on a large-scale server for specific entries, it is often hard to see the forest for the trees. LNAV helps you thin out the information thicket. The curses-based tool prepares the contents of logfiles and highlights timestamps, log levels, and other messages. It understands and analyzes /var/log/syslog, Apache access logs, Strace, and other protocols that include timestamps.

LNAV color highlights important information. For example, it marks warnings in yellow and errors in red. The highlight command followed by a search pattern lets you highlight other entries. You cannot specify the color, however; LNAV chooses the colors itself and changes its choice each time you call it. Filters and search functions help sort the information. The use of regular expressions is possible.

SQL statements can also be used to sort the output. LNAV uses the virtual table function in SQLite 3 to produce rudimentary tables, and you can create your own tables, if needed. Examples using SQL, a collection of integrated LNAV commands, and keyboard shortcuts are available from online help; typing ? displays the help on your screen. The developers have based the shortcuts on common tools. For example, a slash (/) introduces a text search; a colon (:) changes to command mode, and a semicolon (;) changes to SQL mode.

LNAV lives up to its name and helps users navigate logfiles. The tool thus facilitates logfile analysis and evaluation. Sophisticated filtering and search capabilities round out the package.

TOMB 1.4

Creating Encrypted File Containers
License: GPLv3
Alternatives: Cryptmount, TrueCrypt

Tomb creates and manages encrypted containers in the shell. The tool does not use its own algorithms to do this but acts as a wrapper for proven tools such as cryptsetup, dd, and mkfs. Tomb also requires the Z shell. Some commands require root privileges.

Users can create containers in three steps. First, you can call Tomb with the dig parameter to create the container. Options are available for defining the size in megabytes and the name. Second, entering forge generates a keyfile that contains the encryption password. Finally, the lock parameter initializes the container file and locks it with the generated key.

Earlier versions of Tomb also supported the create parameter, which automates all three phases. Although the current version still supports the command, the help and man pages no longer mention it.

The open command lets users open Tomb containers, specifying any additional mount options after -o. By default, the tool mounts the container below /media. The list parameter helps determine which containers are currently open.

Other commands, such as index or search, will index all the data in a specified container, thus enabling searching. More information and application examples are provided by the man page.

Tomb generates encrypted containers in a few steps at the command line and mounts them on the filesystem.

Buy this article as PDF

Express-Checkout as PDF
Price $2.95
(incl. VAT)

Buy Linux Magazine

Get it on Google Play

US / Canada

Get it on Google Play

UK / Australia

Related content

  • Ghost Tracker

    During a long trek through the verbose syslog, really important warnings and errors are scattered along the path. Sometimes a missing message can be the decisive event. Sys admin columnist Charly has now hired a tracker to help him search for clues: Log File Navigator.

  • Fish Shell

    The Fish shell offers some user-friendly features for command line beginners.

  • Command Line: Fish

    The fish shell provides many features that rival the well-known Bash. We examine some highlights.

  • Charly's Column

    If you do not receive a response to a ping, or if the response is seriously delayed, you might like to take this as a warning. But who wants to ping all day? You need a ping-based monitoring utility like Smokeping.

  • Charly's Column: Fish

    Columnist Charly serves up Fish as the "shellfish" of the day. His conclusion: tasty, but not something you would want every day.

comments powered by Disqus

Direct Download

Read full article as PDF:

Price $2.95

Subscribe to our Linux Newsletters
Find Linux and Open Source Jobs
Subscribe to our ADMIN Newsletters
Find SysAdmin Jobs