20. August 2023 in Administration, GNU/Linux, Programmierung.
Some examples:
Find files in current directory that have a size of 400 bytes or more:
sfind -min 400
Find files in /etc that have a size of 50 kilobytes (1 kilobyte = 1024 bytes) or more:
sfind -dir /etc -min 50k
Find files in /var with size between 100 and 500 megabytes, suppress warnings, print sizes in human-readable format:
sfind -dir /var -min 100m -max 500m -quiet -human
Note: Yes, i know, Oracle distributes a tool that is also called „sfind“, but anyway …
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 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.
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:
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.
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
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
Also, the indentation of the printed lines should be removed.