Commands by dbr

Commands by dbr (4)

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sort lines by length

making it "sound" more "natural" language like -- additionally sorting the longest words alphabetically: this approach is using: * to get at all lines of input * post-"for" structure * short-circuit-or in sort: if the lengths are the same, then sort alphabetically otherwise don't even evaluate the right hand side of the or * -C sets all input and ouput channels to utf8
This is sample output - yours may be different.
3

perl -C -e 'print for sort { length $a <=> length $b or $a cmp $b } <>' < /usr/share/dict/words | tail

dbr · 2011-10-20 01:43:25 3
one-line log format for svn

dirrrty: use -p to chomp automatically, substitute all newlines away and then replace the "---" by a newline ? bingo! s/// => s/// is just a cooler way to write s///, s/// which is just the small brother of s///; s/// (comma is an operator!) have fun!
This is sample output - yours may be different.
0

svn log | perl -pe 's/\n//g => s/^-.*/\n/g'

dbr · 2011-10-20 01:20:52 0
Syntax Highlight your Perl code
This is sample output - yours may be different.
1

perl -mText::Highlight -E 'say Text::Highlight->new(ansi => 1)->highlight(Perl => do { local (@ARGV,$/) = shift; <> }) ' path/to/perl-file.pl

dbr · 2011-07-12 04:55:12 1
Find C/C++ source code comments

more idiomatic version of the same, using the flip-flop-operator; also printing lines with '//'-style comments
This is sample output - yours may be different.
0

perl -ne 'print if m{\Q/*\E}x .. m{\Q*/\E}x or m{\/\/}x' *.c

dbr · 2011-07-12 04:41:49 22

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Which processes are listening on a specific port (e.g. port 80)

swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

download newest adminer and rename to it's version accordingly

If the version already downloaded. it will not download again

check open ports without netstat or lsof

Create md5sum of files under the current dir excluding some directories

Useful if you want get all the md5sum of files but you want exclude some directories. If your list of files is short you can make in one command as follow: $ find . -type d $ -name DIR1 -o -name DIR2 $ -prune -o -type f -exec md5sum {} \; Alternatively you can specify a different command to be executed on the resulting files.

Format partition with ext4 but without a journal

For slow flash memory (cheap thumb drive), ext4 is the fastest stable file system for all use cases with no relevant exception: http://www.linuxplanet.com/linuxplanet/tutorials/7208/1 Since we can usually dispense with the benefits of a journal for this type of storage, this is a way to achieve the least awful I/O-speed. Disabling the journal for an existing ext4 partition can be achieved using $ tune2fs -O ^has_journal /dev/sdXN Note that it is often recommended to format removable flash media with ext2, due to the lack of a journal. ext4 has many advantages over ext2 even without the journal, with much better speed as one of the consequences. So the only usecase for ext2 would be compatibility with very old software.

Dump HTTP header using wget

Let me suggest using wget for obtaining the HTTP header only as the last resort because it generates considerable textual overhead. The first ellipsis of the sample output stands for Spider mode enabled. Check if remote file exists. --2009-03-31 20:42:46-- http://www.example.com/ Resolving www.example.com... 208.77.188.166 Connecting to www.example.com|208.77.188.166|:80... connected. HTTP request sent, awaiting response... and the second one looks for Length: 438 [text/html] Remote file exists and could contain further links, but recursion is disabled -- not retrieving.

Detect illegal access to kernel space, potentially useful for Meltdown detection

Based on capsule8 agent examples, not rigorously tested

list block devices

Shows all block devices in a tree with descruptions of what they are.

Rename files in batch

Remind yourself to leave in 15 minutes

If you spend most of your time in front of the terminal, leave is a useful reminder. Leave can have absolute form: leave 1555 reminds you to leave at 3:55PM

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Commands by dbr (4)

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