From b8e6ca2c897ef10e043d8a335f4be12081ffb08c Mon Sep 17 00:00:00 2001
From: Egor Tensin <Egor.Tensin@gmail.com>
Date: Fri, 1 Apr 2022 23:15:26 +0300
Subject: notes/bash: add syntax highlighting

---
 _notes/bash.md | 135 +++++++++++++++++++++++++++++++++------------------------
 1 file changed, 79 insertions(+), 56 deletions(-)

(limited to '_notes')

diff --git a/_notes/bash.md b/_notes/bash.md
index 6529b59..1feef07 100644
--- a/_notes/bash.md
+++ b/_notes/bash.md
@@ -10,17 +10,20 @@ subtitle: best practices
 `"${#xs[@]}"` doesn't work with `nounset` if `xs` wasn't defined, i.e. was
 declared with either of
 
-    local -a xs
-    declare -a xs
-    local -A xs
-    declare -A xs
+```bash
+local -a xs
+declare -a xs
+local -A xs
+declare -A xs
+```
 
 Therefore, if you want to extract the length of an array, append `=()` to the
 statements above.
 
-    local -a xs=()
-    declare -a xs=()
-    ...
+```bash
+local -a xs=()
+declare -a xs=()
+```
 
 And now `"${#xs[@]}"` works with `nounset`.
 It doesn't affect expansion (see below) though.
@@ -29,29 +32,37 @@ It doesn't affect expansion (see below) though.
 
 #### Do
 
-    func ${arr[@]+"${arr[@]}"}
+```bash
+func ${arr[@]+"${arr[@]}"}
+```
 
 #### Don't
 
-    func "${arr[@]}"                # Doesn't work with `nounset`.
-    func "${arr[@]+"${arr[@]}"}"    # Doesn't work properly with `declare -a arr=('')`.
+```bash
+func "${arr[@]}"                # Doesn't work with `nounset`.
+func "${arr[@]+"${arr[@]}"}"    # Doesn't work properly with `declare -a arr=('')`.
+```
 
 ### `unset`
 
 #### Do
 
-    unset -v 'arr[x]'
-    unset -v 'arr[$i]'
+```bash
+unset -v 'arr[x]'
+unset -v 'arr[$i]'
+```
 
 #### Don't
 
-    unset -v arr[x]         # May break due to globbing.
-    unset -v arr[$i]        # The same as above + a possible problem with quotation.
-    unset -v 'arr["x"]'     # Doesn't work for some reason.
-    unset -v 'arr["]"]'     # The same as above; just highlighting the problem with funny characters in array indices.
-    unset -v 'arr["$i"]'    # Also rejected.
+```bash
+unset -v arr[x]         # May break due to globbing.
+unset -v arr[$i]        # The same as above + a possible problem with quotation.
+unset -v 'arr["x"]'     # Doesn't work for some reason.
+unset -v 'arr["]"]'     # The same as above; just highlighting the problem with funny characters in array indices.
+unset -v 'arr["$i"]'    # Also rejected.
 
-    # An insightful discussion on the topic: https://lists.gnu.org/archive/html/help-bash/2016-09/msg00020.html.
+# An insightful discussion on the topic: https://lists.gnu.org/archive/html/help-bash/2016-09/msg00020.html.
+```
 
 `errexit`
 ---------
@@ -63,67 +74,79 @@ useful behaviour.
 
 #### Do
 
-    shopt -s inherit_errexit    # Without this, bar will be executed w/ errexit disabled!
+```bash
+shopt -s inherit_errexit    # Without this, bar will be executed w/ errexit disabled!
 
-    bar() {
-        false
-        echo 'should never see this' >&2
-    }
+bar() {
+    false
+    echo 'should never see this' >&2
+}
 
-    bar_output="$( bar )"
-    foo "$bar_output"
+bar_output="$( bar )"
+foo "$bar_output"
+```
 
 #### Don't
 
-    bar() {
-        false
-        echo 'should never see this' >&2
-    }
+```bash
+bar() {
+    false
+    echo 'should never see this' >&2
+}
 
-    foo "$( bar )"    # Even with errexit, foo will still get executed.
-                      # More than that, the script will print 'should never see this'!
+foo "$( bar )"    # Even with errexit, foo will still get executed.
+                  # More than that, the script will print 'should never see this'!
+```
 
 ### Process substitution
 
 #### Do
 
-    output="$( command )"
+```bash
+output="$( command )"
 
-    while IFS= read -r line; do
-        process_line "$line"
-    done <<< "$output"
+while IFS= read -r line; do
+    process_line "$line"
+done <<< "$output"
+```
 
 #### Don't
 
-    # This causes some bash insanity where you cannot change directories or set
-    # variables inside a loop: http://mywiki.wooledge.org/BashFAQ/024
-    command | while IFS= read -r line; do
-        process_line "$line"
-    done
+```bash
+# This causes some bash insanity where you cannot change directories or set
+# variables inside a loop: http://mywiki.wooledge.org/BashFAQ/024
+command | while IFS= read -r line; do
+    process_line "$line"
+done
 
-    # errexit doesn't work here no matter what:
-    while IFS= read -r line; do
-        process_line "$line"
-    done < <( command )
-    echo 'should never see this'
+# errexit doesn't work here no matter what:
+while IFS= read -r line; do
+    process_line "$line"
+done < <( command )
+echo 'should never see this'
+```
 
 ### Functions
 
 #### Do
 
-    foo() {
-        false
-        echo 'should never see this' >&2
-    }
+```bash
+foo() {
+    false
+    echo 'should never see this' >&2
+}
 
-    foo
-    echo ok
+foo
+echo ok
+```
 
 #### Don't
 
-    if foo; then
-        echo ok       # foo will still print 'should never see this'.
-    fi
+```bash
+if foo; then
+    echo ok       # foo will still print 'should never see this'.
+fi
 
-    foo && echo ok    # Same here.
-    foo || echo ok
+foo && echo ok    # Same here.
+foo || echo ok
+```
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