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#
msgid ""
msgstr ""
msgid ""
"Inspired by Fred Herbert's \"[Awk in 20 Minutes](https://ferd.ca/awk-"
"in-20-minutes.html)\", here's a problem I just solved with a line of Awk: "
"run ShellCheck in all scripts of a repository."
msgstr ""
msgid ""
"In my repositories I usually have Bash and POSIX scripts, which I want to "
"keep tidy with [ShellCheck](https://www.shellcheck.net/). Here's the first "
"version of `assert-shellcheck.sh`:"
msgstr ""
msgid ""
"#!/bin/sh\n"
"set -eu\n"
"\n"
"find . -type f -name '*.sh' -print0 | xargs -0 shellcheck\n"
msgstr ""
msgid ""
"This is the type of script that I copy around to all repositories, and I "
"want it to be capable of working on any repository, without requiring a list"
" of files to run ShellCheck on."
msgstr ""
msgid ""
"This first version worked fine, as all my scripts had the '.sh' ending. But "
"I recently added some scripts without any extension, so `assert-"
"shellcheck.sh` called for a second version. The first attempt was to try "
"grepping the shebang line:"
msgstr ""
msgid ""
"$ grep '^#!/' assert-shellcheck.sh\n"
"#!/usr/sh\n"
msgstr ""
msgid ""
"Good, we have a grep pattern on the first try. Let's try to find all the "
"matching files:"
msgstr ""
msgid ""
"$ find . -type f | xargs grep -l '^#!/'\n"
"./TODOs.org\n"
"./.git/hooks/pre-commit.sample\n"
"./.git/hooks/pre-push.sample\n"
"./.git/hooks/pre-merge-commit.sample\n"
"./.git/hooks/fsmonitor-watchman.sample\n"
"./.git/hooks/pre-applypatch.sample\n"
"./.git/hooks/pre-push\n"
"./.git/hooks/prepare-commit-msg.sample\n"
"./.git/hooks/commit-msg.sample\n"
"./.git/hooks/post-update.sample\n"
"./.git/hooks/pre-receive.sample\n"
"./.git/hooks/applypatch-msg.sample\n"
"./.git/hooks/pre-rebase.sample\n"
"./.git/hooks/update.sample\n"
"./build-aux/with-guile-env.in\n"
"./build-aux/test-driver\n"
"./build-aux/missing\n"
"./build-aux/install-sh\n"
"./build-aux/install-sh~\n"
"./bootstrap\n"
"./scripts/assert-todos.sh\n"
"./scripts/songbooks\n"
"./scripts/compile-readme.sh\n"
"./scripts/ci-build.sh\n"
"./scripts/generate-tasks-and-bugs.sh\n"
"./scripts/songbooks.in\n"
"./scripts/with-container.sh\n"
"./scripts/assert-shellcheck.sh\n"
msgstr ""
msgid ""
"This approach has a problem, though: it includes files ignored by Git, such "
"as `builld-aux/install-sh~`, and even goes into the `.git/` directory and "
"finds sample hooks in `.git/hooks/*`."
msgstr ""
msgid "To list the files that Git is tracking we'll try `git ls-files`:"
msgstr ""
msgid ""
"$ git ls-files | xargs grep -l '^#!/'\n"
"TODOs.org\n"
"bootstrap\n"
"build-aux/with-guile-env.in\n"
"old/scripts/assert-docs-spelling.sh\n"
"old/scripts/build-site.sh\n"
"old/scripts/builder.bats.sh\n"
"scripts/assert-shellcheck.sh\n"
"scripts/assert-todos.sh\n"
"scripts/ci-build.sh\n"
"scripts/compile-readme.sh\n"
"scripts/generate-tasks-and-bugs.sh\n"
"scripts/songbooks.in\n"
"scripts/with-container.sh\n"
msgstr ""
msgid ""
"It looks to be almost there, but the `TODOs.org` entry shows a flaw in it: "
"grep is looking for a `'^#!/'` pattern on any part of the file. In my case, "
"`TODOs.org` had a snippet in the middle of the file where a line started "
"with `#!/bin/sh`."
msgstr ""
msgid ""
"So what we actually want is to match the **first** line against the pattern."
" We could loop through each file, get the first line with `head -n 1` and "
"grep against that, but this is starting to look messy. I bet there is "
"another way of doing it concisely..."
msgstr ""
msgid ""
"Let's try Awk. I need a way to select the line numbers to replace `head -n "
"1`, and to stop processing the file if the pattern matches. A quick search "
"points me to using `FNR` for the former, and `{ nextline }` for the latter. "
"Let's try it:"
msgstr ""
msgid ""
"$ git ls-files | xargs awk 'FNR>1 { nextfile } /^#!\\// { print FILENAME; nextfile }'\n"
"bootstrap\n"
"build-aux/with-guile-env.in\n"
"old/scripts/assert-docs-spelling.sh\n"
"old/scripts/build-site.sh\n"
"old/scripts/builder.bats.sh\n"
"scripts/assert-shellcheck.sh\n"
"scripts/assert-todos.sh\n"
"scripts/ci-build.sh\n"
"scripts/compile-readme.sh\n"
"scripts/generate-tasks-and-bugs.sh\n"
"scripts/songbooks.in\n"
"scripts/with-container.sh\n"
msgstr ""
msgid ""
"Great! Only `TODOs.org` is missing, but the script is much better: instead "
"of matching against any part of the file that may have a shebang-like line, "
"we only look for the first. Let's put it back into the `assert-"
"shellcheck.sh` file and use `NULL` for separators to accommodate files with "
"spaces in the name:"
msgstr ""
msgid ""
"#!/usr/sh\n"
"set -eu\n"
"\n"
"git ls-files -z | \\\n"
" xargs -0 awk 'FNR>1 { nextfile } /^#!\\// { print FILENAME; nextfile }' | \\\n"
" xargs shellcheck\n"
msgstr ""
msgid ""
"This is where I've stopped, but I imagine a likely improvement: match "
"against only `#!/bin/sh` and `#!/usr/bin/env bash` shebangs (the ones I use "
"most), to avoid running ShellCheck on Perl files, or other shebangs."
msgstr ""
msgid ""
"Also when reviewing the text of this article, I found that `{ nextfile }` is"
" a GNU Awk extension. It would be an improvement if `assert-shellcheck.sh` "
"relied on the POSIX subset of Awk for working correctly."
msgstr ""
msgid "title: 'Awk snippet: ShellCheck all scripts in a repository'"
msgstr ""
msgid "date: 2020-12-15"
msgstr ""
msgid "layout: post"
msgstr ""
msgid "lang: en"
msgstr ""
msgid "ref: awk-snippet-shellcheck-all-scripts-in-a-repository"
msgstr ""
msgid "*Update*"
msgstr ""
msgid ""
"After publishing, I could remove `{ nextfile }` and even make the script "
"simpler:"
msgstr ""
msgid ""
"#!/usr/sh\n"
"set -eu\n"
"\n"
"git ls-files -z | \\\n"
" xargs -0 awk 'FNR==1 && /^#!\\// { print FILENAME }' | \\\n"
" xargs shellcheck\n"
msgstr ""
msgid "Now both the shell and Awk usage are POSIX compatible."
msgstr ""
#~ msgid ""
#~ "title: 'Awk snippet: ShellCheck all scripts in a repository'\n"
#~ "date: 2020-12-15\n"
#~ "layout: post\n"
#~ "lang: en\n"
#~ "ref: awk-snippet-shellcheck-all-scripts-in-a-repository"
#~ msgstr ""
|
