brandon/oam
1
0
Fork 0
mirror of https://gitea.com/mcereda/oam.git synced 2026-02-09 13:44:24 +00:00
Code Issues Packages Projects Releases Wiki Activity

Generally improved notes on shells

Browse Source
This commit is contained in:
Michele Cereda
2022-10-16 01:53:24 +02:00
parent 07632ba5a2
commit ad0c06011b
2 changed files with 78 additions and 20 deletions
Download Patch File Download Diff File Expand all files Collapse all files

17
knowledge base/bash.md
View File

@@ -3,14 +3,21 @@
## TL;DR
```sh
# Declare functions.
functionName () { … }
function functionName { … }
# Declare functions on a single line.
functionName () { command1 ; … ; command N ; }
# Run a command or function on exit, kill or error.
trap "rm -f $tempfile" EXIT SIGTERM ERR
trap function-name EXIT SIGTERM ERR
# Disable CTRL-C
# Disable CTRL-C.
trap "" SIGINT
# Re-enable CTRL-C
# Re-enable CTRL-C.
trap - SIGINT
# Bash 3 and `sh` have no built-in means to convert case of a string, but the
@@ -23,7 +30,7 @@ echo ${name,,}
echo ${name^^}
```
## Files loading order
## Startup files loading order
On startup:
@@ -39,6 +46,10 @@ Upon exit:
1. (if login shell) `~/.bash_logout`
1. (if login shell) `/etc/bash_logout`
## Functions
A function automatically returns the exit code of the last command in it.
## Check if a script is sourced by another
```sh

81
knowledge base/zsh.md
View File

@@ -1,14 +1,52 @@
# ZSH
1. [TL;DR](#tldr)
2. [Alias expansion](#alias-expansion)
3. [Parameter expansion](#parameter-expansion)
1. [Parameter substitution](#parameter-substitution)
1. [Check if a variable is set](#check-if-a-variable-is-set)
2. [Provide a default value](#provide-a-default-value)
3. [Just substitute with its value if set](#just-substitute-with-its-value-if-set)
4. [Set a default value and substitute](#set-a-default-value-and-substitute)
5. [Fail on missing value](#fail-on-missing-value)
2. [Matching and replacement](#matching-and-replacement)
4. [Arrays](#arrays)
5. [Tests](#tests)
6. [Find broken symlinks in the current directory](#find-broken-symlinks-in-the-current-directory)
7. [Key bindings](#key-bindings)
8. [Configuration](#configuration)
1. [Config files read order](#config-files-read-order)
2. [History](#history)
3. [Completion](#completion)
4. [Prompt management](#prompt-management)
5. [Automatic source of files in a folder](#automatic-source-of-files-in-a-folder)
9. [Frameworks](#frameworks)
10. [Plugins](#plugins)
11. [Troubleshooting](#troubleshooting)
1. [The delete, end and/or home keys are not working as intended](#the-delete-end-andor-home-keys-are-not-working-as-intended)
2. [Compinit warnings of insecure directories and files](#compinit-warnings-of-insecure-directories-and-files)
12. [Further readings](#further-readings)
## TL;DR
Startup file sequence:
Startup files load sequence:
1. `/etc/zshenv` and `${ZDOTDIR}/.zshenv`
1. **login** shells only: `/etc/zprofile` and `${ZDOTDIR}/.zprofile`
1. **interactive** shell only: `/etc/zshrc` and `${ZDOTDIR}/.zshrc`
1. **login** shells only: `/etc/zlogin` and `${ZDOTDIR}/.zlogin`
1. **upon exit**: `/etc/zlogout` and `${ZDOTDIR}/.zlogout`
1. `/etc/zshenv`
1. `${ZDOTDIR}/.zshenv`
1. **login** shells only:
1. `/etc/zprofile`
1. `${ZDOTDIR}/.zprofile`
1. **interactive** shells only:
1. `/etc/zshrc`
1. `${ZDOTDIR}/.zshrc`
1. **login** shells only:
1. `/etc/zlogin`
1. `${ZDOTDIR}/.zlogin`
Exit files load sequence:
1. `/etc/zlogout`
1. `${ZDOTDIR}/.zlogout`
Aliases are expanded when the function definition is parsed, not when the function is executed. Define aliases **before** functions to avoid problems.
@@ -59,9 +97,10 @@ When one writes an alias, one can also press `ctrl-x` followed by `a` to see the
## Parameter expansion
Parameter expansions can involve flags like `${(@kv)aliases}` and other operators such as `${PREFIX:-"/usr/local"}`. Parameter expansions can also be nested.
Parameter expansions can involve flags like `${(@kv)aliases}` and other operators such as `${PREFIX:-"/usr/local"}`.
Nested parameters expand from the inside out.
If the parameter is a **scalar** then the value, if any, is substituted:
If the parameter is a **scalar** (a number or string) then the value, if any, is substituted:
```sh
$ scalar='hello'
@@ -69,7 +108,7 @@ $ echo "$scalar"
hello
```
The braces are required if the expansion is to be followed by a letter, digit or underscore that is not to be interpreted as part of name:
Curly braces are required if the expansion is followed by letters, digits or underscores that are not to be interpreted as part of name:
```sh
$ echo "${scalar}_world"
@@ -84,18 +123,19 @@ $ echo "${array[@]}"
hello world
```
The two forms are equivalent:
The two forms `array[@]` and `(@)array` are equivalent:
```sh
$ echo "${(@)array}"
hello world
```
### Substitution
### Parameter substitution
#### Check if set
#### Check if a variable is set
If _name_ is set then its value is substituted by _1_, otherwise by _0_:
Use the form `+parameterName`.
If _name_ is set, even to an empty string, then its value is substituted by _1_, otherwise by _0_:
```sh
$ typeset name='tralala'
@@ -113,6 +153,7 @@ $ echo "${+name}"
#### Provide a default value
Use the forms `parameterName-defaultValue` or `parameterName:-defaultValue`.
If _name_ is set then substitute its value, otherwise substitute _word_:
```sh
@@ -122,7 +163,7 @@ tralala
$ name=''
$ echo "${name-word}"
(empty line)
(empty string)
$ unset name
$ echo "${name-word}"
@@ -146,11 +187,15 @@ word
$ unset name
$ echo "${name:-word}"
word
$ echo "${:-word}"
word
```
#### Just substitute
#### Just substitute with its value if set
If _name_ is set then substitute _word_, otherwise substitute nothing:
Use the forms `parameterName+defaultValue` or `parameterName:+defaultValue`.
If _name_ is set, then substitute it with its value, otherwise substitute nothing:
```sh
$ name='tralala'
@@ -166,7 +211,7 @@ $ echo "${name+word}"
(empty line)
```
In the second form, only substitute its value if _name_ is non-null:
In the second form, only substitute its value if _name_ is set **and** non-null:
```sh
$ name='tralala'
@@ -184,6 +229,7 @@ $ echo "${name:+word}"
#### Set a default value and substitute
Use the forms `parameterName=defaultValue`, `parameterName:=defaultValue` or `parameterName::=defaultValue`.
In the first form, if _name_ is unset then set it to _word_:
```sh
@@ -252,6 +298,7 @@ word
#### Fail on missing value
Use the forms `parameterName?defaultValue` or `parameterName:?defaultValue`.
In the first form, if _name_ is set then substitute its value, otherwise print _word_ and exit from the shell.
```sh