From c77a95531f643dd91a740322294ba2e5d5c54c46 Mon Sep 17 00:00:00 2001 From: Paul Buetow Date: Mon, 29 Nov 2021 12:46:29 +0200 Subject: Publishing new version --- gemfeed/2008-06-26-perl-poetry.md | 2 +- gemfeed/2021-11-28-bash-golf-part-1.md | 430 +++++++++++++++++++++++ gemfeed/2021-11-28-bash-golf-part-2.draft.md | 488 +++++++++++++++++++++++++++ gemfeed/index.md | 1 + index.md | 3 +- 5 files changed, 922 insertions(+), 2 deletions(-) create mode 100644 gemfeed/2021-11-28-bash-golf-part-1.md create mode 100644 gemfeed/2021-11-28-bash-golf-part-2.draft.md diff --git a/gemfeed/2008-06-26-perl-poetry.md b/gemfeed/2008-06-26-perl-poetry.md index aaa27b09..7a12e865 100644 --- a/gemfeed/2008-06-26-perl-poetry.md +++ b/gemfeed/2008-06-26-perl-poetry.md @@ -157,7 +157,7 @@ This is perl, v5.8.8 built for i386-freebsd-64int ## More... -Did you like what you saw? Have a look at Github to see my other poems too: +Did you like what you saw? Have a look at Codeberg to see my other poems too: [https://codeberg.org/snonux/perl-poetry](https://codeberg.org/snonux/perl-poetry) diff --git a/gemfeed/2021-11-28-bash-golf-part-1.md b/gemfeed/2021-11-28-bash-golf-part-1.md new file mode 100644 index 00000000..c05be0d5 --- /dev/null +++ b/gemfeed/2021-11-28-bash-golf-part-1.md @@ -0,0 +1,430 @@ +# Bash Golf Part 1 + +``` + + '\ . . |>18>> + \ . ' . | + O>> . 'o | + \ . | + /\ . | + / / .' | +jgs^^^^^^^`^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + Art by Joan Stark +``` + +> Published by Paul Buetow 2021-11-29 + +This is the first blog post about my Bash Golf series. This series is random Bash tips, tricks and weirdnesses I came across. It's a collection of smaller articles I wrote in an older (in German language) blog, which I translated and refreshed with some new content. + +## TCP/IP networking + +You probably know the Netcat tool, which is a swiss army knife for TCP/IP networking on the command line. But did you know that the Bash natively supports TCP/IP networking? + +Have a look here how that works: + +``` +❯ cat < /dev/tcp/time.nist.gov/13 + +59536 21-11-18 08:09:16 00 0 0 153.6 UTC(NIST) * +``` + +The Bash treats /dev/tcp/HOST/PORT in a special way so that it is actually establishing a TCP connection to HOST:PORT. The example above redirects the TCP output of the time-server to cat and cat is printing it on standard output (stdout). + +A more sophisticated example is firing up an HTTP request. Let's create a new read-write (rw) file descriptor (fd) 5, redirect the HTTP request string to it, and then read the response back: + +``` +❯ exec 5<>/dev/tcp/google.de/80 +❯ echo -e "GET / HTTP/1.1\nhost: google.de\n\n" >&5 +❯ cat <&5 | head +HTTP/1.1 301 Moved Permanently +Location: http://www.google.de/ +Content-Type: text/html; charset=UTF-8 +Date: Thu, 18 Nov 2021 08:27:18 GMT +Expires: Sat, 18 Dec 2021 08:27:18 GMT +Cache-Control: public, max-age=2592000 +Server: gws +Content-Length: 218 +X-XSS-Protection: 0 +X-Frame-Options: SAMEORIGIN +``` + +You would assume that this also works with the ZSH, but it doesn't. This is one of the few things which don't work with the ZSH but in the Bash. There might be plugins you could use for ZSH to do something similar, though. + +## Process substitution + +The idea here is, that you can read the output (stdout) of a command from a file descriptor: + +``` +❯ uptime # Without process substitution + 10:58:03 up 4 days, 22:08, 1 user, load average: 0.16, 0.34, 0.41 + +❯ cat <(uptime) # With process substitution + 10:58:16 up 4 days, 22:08, 1 user, load average: 0.14, 0.33, 0.41 + +❯ stat <(uptime) + File: /dev/fd/63 -> pipe:[468130] + Size: 64 Blocks: 0 IO Block: 1024 symbolic link +Device: 16h/22d Inode: 468137 Links: 1 +Access: (0500/lr-x------) Uid: ( 1001/ paul) Gid: ( 1001/ paul) +Context: unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 +Access: 2021-11-20 10:59:31.482411961 +0000 +Modify: 2021-11-20 10:59:31.482411961 +0000 +Change: 2021-11-20 10:59:31.482411961 +0000 + Birth: - +``` + +This example doesn't make any sense practically speaking, but it clearly demonstrates how process substitution works. The standard output pipe of "uptime" is redirected to an anonymous file descriptor. That fd then is opened by the "cat" command as a regular file. + +A useful use case is displaying the differences of two sorted files: + +``` +❯ echo a > /tmp/file-a.txt +❯ echo b >> /tmp/file-a.txt +❯ echo c >> /tmp/file-a.txt +❯ echo b > /tmp/file-b.txt +❯ echo a >> /tmp/file-b.txt +❯ echo c >> /tmp/file-b.txt +❯ echo X >> /tmp/file-b.txt +❯ diff -u <(sort /tmp/file-a.txt) <(sort /tmp/file-b.txt) +--- /dev/fd/63 2021-11-20 11:05:03.667713554 +0000 ++++ /dev/fd/62 2021-11-20 11:05:03.667713554 +0000 +@@ -1,3 +1,4 @@ + a + b + c ++X +❯ echo X >> /tmp/file-a.txt # Now, both files have the same content again. +❯ diff -u <(sort /tmp/file-a.txt) <(sort /tmp/file-b.txt) +❯ +``` + +Another example is displaying the differences of two directories: + +``` +❯ diff -u <(ls ./dir1/ | sort) <(ls ./dir2/ | sort) +``` + +More (Bash golfing) examples: + +``` +❯ wc -l <(ls /tmp/) /etc/passwd <(env) + 24 /dev/fd/63 + 49 /etc/passwd + 24 /dev/fd/62 + 97 total +❯ + +❯ while read foo; do +> echo $foo +> done < <(echo foo bar baz) +foo bar baz +❯ +``` + +So far, we only used process substitution for stdout redirection. But it also works for stdin. The following two commands result into the same outcome, but the second one is writing the tar data stream to an anonymous file descriptor which is substituted by the "bzip2" command reading the data stream from stdin and compressing it to its own stdout, which then gets redirected to a file: + +``` +❯ tar cjf file.tar.bz2 foo +❯ tar cjf >(bzip2 -c > file.tar.bz2) foo +``` + +Just think a while and see whether you understand fully what is happening here. + +## Grouping + +Command grouping can be quite useful for combining the output of multiple commands: + +``` +❯ { ls /tmp; cat /etc/passwd; env; } | wc -l +97 +❯ ( ls /tmp; cat /etc/passwd; env; ) | wc -l +97 +``` + +But wait, what is the difference between curly braces and normal braces? I assumed that the normal braces create a subprocess whereas the curly ones don't, but I was wrong: + +``` +❯ echo $$ +62676 +❯ { echo $$; } +62676 +❯ ( echo $$; ) +62676 +``` + +One difference is, that the curly braces require you to end the last statement with a semicolon, whereas with the normal braces you can omit the last semicolon: + +``` +❯ ( env; ls ) | wc -l +27 +❯ { env; ls } | wc -l +> +> ^C +``` + +In case you know more (subtle) differences, please write me an E-Mail and let me know. + +## Expansions + +Let's start with simple examples: + +``` +❯ echo {0..5} +0 1 2 3 4 5 +❯ for i in {0..5}; do echo $i; done +0 +1 +2 +3 +4 +5 +``` + +You can also add leading 0 or expand to any number range: + +``` +❯ echo {00..05} +00 01 02 03 04 05 +❯ echo {000..005} +000 001 002 003 004 005 +❯ echo {201..205} +201 202 203 204 205 +``` + +It also works with letters: + +``` +❯ echo {a..e} +a b c d e +``` + +Now it gets interesting. The following takes a list of words and expands it so that all words are quoted: + +``` +❯ echo \"{These,words,are,quoted}\" +"These" "words" "are" "quoted" +``` + +Let's also expand to the cross product of two given lists: + +``` +❯ echo {one,two}\:{A,B,C} +one:A one:B one:C two:A two:B two:C +❯ echo \"{one,two}\:{A,B,C}\" +"one:A" "one:B" "one:C" "two:A" "two:B" "two:C" +``` + +Just because we can: + +``` +❯ echo Linux-{one,two,three}\:{A,B,C}-FreeBSD +Linux-one:A-FreeBSD Linux-one:B-FreeBSD Linux-one:C-FreeBSD Linux-two:A-FreeBSD Linux-two:B-FreeBSD Linux-two:C-FreeBSD Linux-three:A-FreeBSD Linux-three:B-FreeBSD Linux-three:C-FreeBSD +``` + +## - aka stdin and stdout placeholder + +Some commands and Bash builtins use "-" as a placeholder for stdin and stdout: + +``` +❯ echo Hello world +Hello world +❯ echo Hello world | cat - +Hello world +❯ cat - <18>> + \ . ' . | + O>> . 'o | + \ . | + /\ . | + / / .' | +jgs^^^^^^^`^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + Art by Joan Stark +``` + +> Published by Paul Buetow 2021-11-29 + +This is the second blog post about my Bash Golf series. This series is random Bash tips, tricks and weirdnesses I came across. It's a collection of smaller articles I wrote in an older (in German language) blog, which I translated and refreshed with some new content. + +## Redirection + +Let's have a closer look at Bash redirection. As you might already know that there are 3 standard file descriptors: + +* 0 aka stdin (standard input) +* 1 aka stdout (standard output) +* 2 aka stderr (standard error output) + +These are most certainly the ones you are using on regular basis. "/proc/self/fd" lists all file descriptors which are open by the current process (in this case: the current bash shell itself): + +``` +❯ ls -l /proc/self/fd/ +total 0 +lrwx------. 1 paul paul 64 Nov 23 09:46 0 -> /dev/pts/9 +lrwx------. 1 paul paul 64 Nov 23 09:46 1 -> /dev/pts/9 +lrwx------. 1 paul paul 64 Nov 23 09:46 2 -> /dev/pts/9 +lr-x------. 1 paul paul 64 Nov 23 09:46 3 -> /proc/162912/fd +``` + +The following examples demonstrate two different ways to accomplish the same thing. The difference is that the first command is directly printing out "Foo" to stdout and the second command is explicitly redirecting stdout to its own stdout file descriptor: + +``` +❯ echo Foo +Foo +❯ echo Foo > /proc/self/fd/0 +Foo +``` + +Other useful redirections are: + +* Redirect stderr to stdin: "echo foo 2>&1" +* Redirect stdin to stderr: "echo foo >&2" + +It is, however, not possible to redirect multiple times within the same command. E.g. the following won't work. You would expect stdin to be redirected to stderr and then stderr to be redirected to /dev/null. But as the example shows, Foo is still printed out: + +``` +❯ echo Foo 1>&2 2>/dev/null +Foo +``` + +This is where you can use grouping (neither of these commands will print out anything to stdout): + +``` +❯ { echo Foo 1>&2; } 2>/dev/null +❯ ( echo Foo 1>&2; ) 2>/dev/null +❯ { { { echo Foo 1>&2; } 2>&1; } 1>&2; } 2>/dev/null +❯ ( ( ( echo Foo 1>&2; ) 2>&1; ) 1>&2; ) 2>/dev/null +❯ +``` + +A handy way to list all open file descriptors is to use the "lsof" command (that's not a Bash built-in), whereas $$ is the process id (pid) of the current shell process: + +``` +❯ lsof -a -p $$ -d0,1,2 +COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME +bash 62676 paul 0u CHR 136,9 0t0 12 /dev/pts/9 +bash 62676 paul 1u CHR 136,9 0t0 12 /dev/pts/9 +bash 62676 paul 2u CHR 136,9 0t0 12 /dev/pts/9 +``` + +Let's create our own descriptor "3" for redirection to a file named "foo": + +``` +❯ touch foo +❯ exec 3>foo # This opens fd 3 and binds it to file foo. +❯ ls -l /proc/self/fd/3 +l-wx------. 1 paul paul 64 Nov 23 10:10 \ + /proc/self/fd/3 -> /home/paul/foo +❯ cat foo +❯ echo Bratwurst >&3 +❯ cat foo +Bratwurst +❯ exec 3>&- # This closes fd 3. +❯ echo Steak >&3 +-bash: 3: Bad file descriptor +``` + +You can also override the default file descriptors, as the following example script demonstrates: + +``` +❯ cat grandmaster.sh +#!/usr/bin/env bash + +# Write a file data-file containing two lines +echo Learn You a Haskell > data-file +echo for Great Good >> data-file + +# Link fd with fd 6 (saves default stdin) +exec 6<&0 + +# Overwrite stdin with data-file +exec < data-file + +# Read the first two lines from it +declare LINE1 LINE2 +read LINE1 +read LINE2 + +# Print them +echo First line: $LINE1 +echo Second line: $LINE2 + +# Restore default stdin and delete fd 6 +exec 0<&6 6<&- +``` + +Let's execute it: + +``` +❯ chmod 750 ./grandmaster.sh +❯ ./grandmaster.sh +First line: Learn You a Haskell +Second line: for Great Good +``` + +## HERE + +I have mentioned HERE-documents and HERE-strings already in this post. Let's do some more examples. The following "cat" receives a multi line string from stdin. In this case, the input multi line string is a HERE-document. As you can see, it also interpolates variables (in this case the output of "date" running in a subshell). + +``` +❯ cat < Hello World +> It’s $(date) +> END +Hello World +It's Fri 26 Nov 08:46:52 GMT 2021 +``` + +You can also write it the following way, but that's less readable (it's good for an obfuscation contest): + +``` +❯ < Hello Universe +> It’s $(date) +> END +Hello Universe +It's Fri 26 Nov 08:47:32 GMT 2021 +``` + +Besides of an HERE-document, there is also a so-called HERE-string. Besides of... + +``` +❯ declare VAR=foo +❯ if echo "$VAR" | grep -q foo; then +> echo '$VAR ontains foo' +> fi +$VAR ontains foo +``` + +...you can use a HERE-string like that: + +``` +❯ if grep -q foo <<< "$VAR"; then +> echo '$VAR contains foo' +> fi +$VAR contains foo +``` + +Or even shorter, you can do: + +``` +❯ grep -q foo <<< "$VAR" && echo '$VAR contains foo' +$VAR contains foo +``` + +You can also use a Bash regex to accomplish the same thing, but the points of the examples so far were to demonstrate HERE-{documents,strings} and not Bash regular expressions: + +``` +❯ if [[ "$VAR" =~ foo ]]; then echo yay; fi +yay +``` + +You can also use it with "read": + +``` +❯ read a <<< ja +❯ echo $a +ja +❯ read b <<< 'NEIN!!!' +❯ echo $b +NEIN!!! +❯ dumdidumstring='Learn you a Golang for Great Good' +❯ read -a words <<< "$dumdidumstring" +❯ echo ${words[0]} +Learn +❯ echo ${words[3]} +Golang +``` + +The following is good for an obfuscation contest too: + +``` +❯ echo 'I like Perl too' > perllove.txt +❯ cat - perllove.txt <<< "$dumdidumstring" +Learn you a Golang for Great Good +I like Perl too +``` + +## RANDOM + +Random is a special built-in variable containing a different pseudo random number each time it's used. + +``` +❯ echo $RANDOM +11811 +❯ echo $RANDOM +14997 +❯ echo $RANDOM +9104 +``` + +That's very useful if you want to randomly delay the execution of your scripts when you run it on many servers concurrently, just to spread the server load (which might be caused by the script run) better. + +Let's say you want to introduce a random delay of 1 minute. You can accomplish it with: + +``` +❯ cat ./calc_answer_to_ultimate_question_in_life.sh +#!/usr/bin/env bash + +declare -i MAX_DELAY=60 + +random_delay () { + local -i sleep_for=$((RANDOM % MAX_DELAY)) + echo "Delaying script execution for $sleep_for seconds..." + sleep $sleep_for + echo 'Continuing script execution...' +} + +main () { + random_delay + # From here, do the real work. Calculating the answer to + # the ultimate question can take billions of years.... + : .... +} + +main + +❯ +❯ ./calc_answer_to_ultimate_question_in_life.sh +Delaying script execution for 42 seconds... +Continuing script execution... +``` + +## set -x and set -e and pipefile + +In my opinion, -x and -e and pipefile are the most useful Bash options. Let's have a look at them one after another. + +### -x + +-x prints commands and their arguments as they are executed. This helps to develop and debug your Bash code: + +``` +❯ set -x +❯ square () { local -i num=$1; echo $((num*num)); } +❯ num=11; echo "Square of $num is $(square $num)" ++ num=11 +++ square 11 +++ local -i num=11 +++ echo 121 ++ echo 'Square of 11 is 121' +Square of 11 is 121 +``` + +However, you need to set -x for any subshell as well in order to make it work there too: + +``` +❯ num=12; echo "Square of $num is $(set -x;square $num)" ++ num=12 +++ set -x +++ square 12 +++ local -i num=12 +++ echo 144 ++ echo 'Square of 12 is 144' +Square of 12 is 144 +❯ +``` + +You can also set it when calling an external script without modifying the script itself: + +``` +❯ bash -x ./half_broken_script_to_be_debugged.sh +``` + +Let's do that on one of the example scripts we covered earlier: + +``` +❯ bash -x ./grandmaster.sh ++ bash -x ./grandmaster.sh ++ echo Learn You a Haskell ++ echo for Great Good ++ exec ++ exec ++ declare LINE1 LINE2 ++ read LINE1 ++ read LINE2 ++ echo First line: Learn You a Haskell +First line: Learn You a Haskell ++ echo Second line: for Great Good +Second line: for Great Good ++ exec +❯ +``` + +### -e + +This is a very important option you want to use when you are paranoid. This means, you should always "set -e" in your scripts when you need to make absolutely sure that your script runs successfully (with that I mean that no command should exit with an unexpected status code). + +Before we dig dipper, this blog article of mine might interest you too, it describes more techniques to make your scripts running safely: + +[Defensive DevOps](./2021-10-22-defensive-devops.md) + +Ok, let's dig deeper: + +``` +❯ help set | grep -- -e + -e Exit immediately if a command exits with a non-zero status. +``` + +As you can see in the following example, the Bash terminates after the execution of "grep" as "foo" is not matching "bar". Therefore, grep exits with 1 (unsuccessfully) and the shell aborts. And therefore, "bar" will not be printed out anymore: + +``` +❯ bash -c 'set -e; echo hello; grep -q bar <<< foo; echo bar' +hello +❯ echo $? +1 +``` + +Whereas the outcome changes when the regex matches: + +``` +❯ bash -c 'set -e; echo hello; grep -q bar <<< barman; echo bar' +hello +bar +❯ echo $? +0 +``` + +So does it mean that grep will always make the shell terminate whenever its exit code isn't 0? This will render "set -e" quite unusable. Frankly, there are other commands where an exit status other than 0 should not terminate the whole script abruptly. Usually, what you want is to branch your code based on the outcome (exit code) of a command: + +``` +❯ bash -c 'set -e +> grep -q bar <<< foo +> if [ $? -eq 0 ]; then +> echo "matching" +> else +> echo "not matching" +> fi' +❯ echo $? +1 +``` + +...but the example above won't reach any of the branches and won't print out anything, as the script terminates right after grep. + +The proper solution is to use grep as an expression in a conditional (e.g. in an if-else statement): + +``` +❯ bash -c 'set -e +> if grep -q bar <<< foo; then +> echo "matching" +> else +> echo "not matching" +> fi' +not matching +❯ echo $? +0 +❯ bash -c 'set -e +> if grep -q bar <<< barman; then +> echo "matching" +> else +> echo "not matching" +> fi' +matching +❯ echo $? +0 +``` + +You can also temporally undo "set -e" if there is no other way: + +``` +❯ cat ./e.sh +#!/usr/bin/env bash + +set -e + +foo () { + local arg="$1"; shift + + if [ -z "$arg" ]; then + arg='You!' + fi + echo "Hello $arg" +} + +bar () { + # Temporally disable e + set +e + local arg="$1"; shift + # Enable e again. + set -e + + if [ -z "$arg" ]; then + arg='You!' + fi + echo "Hello $arg" +} + +# Will succeed +bar World +foo Universe +bar + +# Will terminate the script +foo + +❯ ./e.sh +Hello World +Hello Universe +Hello You! +``` + +Why does calling "foo" with no arguments make the script terminate? Because as no argument was given, the "shift" won't have anything to do as the argument list $@ is empty, and therefore "shift" fails with a non-zero status. + +Why would you want to use "shift" after function-local variable assignments? Have a look at my personal Bash coding style guide for an explanation :-): + +[./2021-05-16-personal-bash-coding-style-guide.md](./2021-05-16-personal-bash-coding-style-guide.md) + +### pipefail + +The pipefail option makes it so that not only the exit code of the last command of the pipe counts regards its exit code but any command of the pipe: + +``` +❯ help set | grep pipefail -A 2 + pipefail the return value of a pipeline is the status of + the last command to exit with a non-zero status, + or zero if no command exited with a non-zero status +``` + +The following greps for paul in passwd and converts all lowercase letters to uppercase letters. The exit code of the pipe is 0, as the last command of the pipe (converting from lowercase to uppercase) succeeded: + +``` +0 +❯ grep paul /etc/passwd | tr '[a-z]' '[A-Z]' +PAUL:X:1000:1000:PAUL BUETOW:/HOME/PAUL:/BIN/BASH +❯ echo $? +0 +``` + +Let's look at another example, where "TheRock" doesn't exist in the passwd file. However, the pipes exit status is still 0 (success). This is so because the last command ("tr" in this case) still succeeded. It is just that it didn't get any input on stdin to process: + +``` +❯ grep TheRock /etc/passwd +❯ echo $? +1 +❯ grep TheRock /etc/passwd | tr '[a-z]' '[A-Z]' +❯ echo $? +0 +``` + +To change this behaviour, pipefile can be used. Now, the pipes exit status is 1 (fail), because the pipe contains at least one command (in this case grep) which exited with status 1: + +``` +❯ set -o pipefail +❯ grep TheRock /etc/passwd | tr '[a-z]' '[A-Z]' +❯ echo $? +1 +``` + +E-Mail me your thoughts at comments@mx.buetow.org! + +[Go back to the main site](../) diff --git a/gemfeed/index.md b/gemfeed/index.md index b8023a16..1025a772 100644 --- a/gemfeed/index.md +++ b/gemfeed/index.md @@ -2,6 +2,7 @@ ## Having fun with computers! +[2021-11-28 (1181 words) - Bash Golf Part 1](./2021-11-28-bash-golf-part-1.md) [2021-10-22 (2276 words) - Defensive DevOps](./2021-10-22-defensive-devops.md) [2021-09-12 (1365 words) - Keep it simple and stupid](./2021-09-12-keep-it-simple-and-stupid.md) [2021-08-01 (2919 words) - On being Pedantic about Open-Source](./2021-08-01-on-being-pedantic-about-open-source.md) diff --git a/index.md b/index.md index 0b430769..1a055d85 100644 --- a/index.md +++ b/index.md @@ -33,7 +33,7 @@ If you reach this site via the modern web, please read this: My name is Paul Buetow, and this is my internet site. You can call me a Linux/*BSD enthusiast and hobbyist. Although I also have many other interests, you will encounter mostly (if not only) technical content on this site. -I have published some Open-Source software; you will find references to it on this site or my GitHub page(s). I also read a lot of tech newsletters and blogs. I re-share the most interesting ones on my social media feeds. You can find links to my GitHub pages and my social media accounts on my contact information page: +I have published some Open-Source software; you will find references to it on this site. I also read a lot of tech newsletters and blogs. I re-share the most interesting ones on my social media feeds. You can find links to my Codeberg page and my social media accounts on my contact information page: [Contact information](./contact-information.md) @@ -52,6 +52,7 @@ I have also compiled a list of resources that made an impact on me: I have switched blog software multiple times. I might be backfilling some of the older articles here. So please don't wonder when suddenly old posts appear here. +[2021-11-28 - Bash Golf Part 1](./gemfeed/2021-11-28-bash-golf-part-1.md) [2021-10-22 - Defensive DevOps](./gemfeed/2021-10-22-defensive-devops.md) [2021-09-12 - Keep it simple and stupid](./gemfeed/2021-09-12-keep-it-simple-and-stupid.md) [2021-08-01 - On being Pedantic about Open-Source](./gemfeed/2021-08-01-on-being-pedantic-about-open-source.md) -- cgit v1.2.3