20. August 2023 in Administration, GNU/Linux, Technik.
The OrangePi Zero 2 H616/1GByte is capable of running PiKVM. I find this an interesting development, because if i only want the KVM functionality, a full-blown Raspberry Pi 4 with all its CPU resources, multiple Gigabytes of RAM and peripheral devices seems somewhat of an overkill. I am aware that the latest official PiKVM, the V4Plus uses a Raspberry Pi Compute Module with 2 GB RAM, but mine is still smaller. 🙂
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20. August 2023 in GNU/Linux, Programmierung.
Some configuration and output text formats contain sections like the following:
foo:
value1
value2
bar:
value 3
In this article, two scripts are presented that print all consecutive indented lines that follow a non-indented line that matches a search pattern given by a regular expression.
This means, given the single argument foo and the standard input above, the scripts should
- determine the line that matches foo and
- print the following two lines, but no other lines.
Also, the indentation of the printed lines should be removed.
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19. August 2023 in Sonstiges.
Ein paar Fotos aus der Ostschweiz, Kantone St. Gallen und Appenzell Innerrhoden:
Blick aus dem Hotelfenster auf St. Gallen Hauptbahnhof
Donnerstag morgens in St. Gallen Altstadt
St. Gallen Altstadt spät abends
Ein Laden in Appenzell
Blick das Rheintal hinauf (links des Rheins ist Liechtenstein)
Bergblumen
Bergblumen am Gipfel des Hohen Kastens, vor den Fenstern des Drehrestaurants
Panorama West-Süd-Südost vom Hohen Kasten
Blick aufs Appenzeller Land, aufgenommen von der Terrasse des Restaurants Waldegg in Teufen
Blick auf den Bodensee aus einem Fenster des Rohrschacher Museums im Kornhaus
Hauptstraße in Rohrschach
19. September 2023 in Administration, GNU/Linux, Programmierung, Technik.
The tool presented here, „Simple Apt Update“ (simple-apt-update) is nothing more than a front-end to the non-interactive execution of apt-get update|full-upgrade and apt list --upgradeable. It can look like this:
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20. August 2023 in GNU/Linux, Programmierung.
The stat command from GNU core utilities features not only a --format FORMAT option but also a --printf FORMAT one, the difference being that the latter allows for backslash escapes such as \n.
This allows for custom per-file report formats containing newlines, for example:
stat --printf 'Name: %n\nSize: %s Bytes\n' /etc/passwd
If the format string becomes more complex, the command line soon becomes unwieldy, such as:
stat --printf 'Name: %n\nOwner ID: %u\nSize: %s Bytes\nLast accessed: %x\n' /etc/passwd
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20. August 2023 in Administration, GNU/Linux, Programmierung.
The Bourne Again Shell script presented in this article demonstrates techniques related to capturing and logging output (standard output and standard error stream) of a script into a log file while also delivering it to the regular output destinations (for example the terminal or whatever the caller has chosen to redirect to). Some questions are addressed:
- How to „clone“ standard output and standard error stream of a shell script to a single log file?
- Are the messages from both streams interleaved into a single file in the appropriate order?
- Can a script perform output cloning for some portions of its procedure while skipping it for others?
- Are there specific requirements for output that is to be cloned to a file?
- Are there best practices when a script modifies its own output redirections?
The example provided below has been tested on GNU/Linux using GNU „bash“ version 5 and „tee“ version 8.32 from GNU coreutils. It uses the Bash-only feature of process substitution. An implementation in POSIX Shell (possibly using only POSIX tools) would be more difficult.
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20. August 2023 in GNU/Linux, Programmierung.
Given a file containing bytes of text with lines separated by the newline character (\n), one of these lines can be said to be „the last line of the file“; it is a sequence of bytes occurring in the file, for which holds:
- The sequence contains no newline character, and
- the sequence is followed by at most one newline character and no other bytes.
The task at hand is, using shell utilities, to write a procedure that makes sure that a given file contains a last line that contains a desired sequence of text characters.
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