# Style Guide In order to make LinuxGSM as coherent as possible, we adopted some code conventions to follow.\ Here are some of them. ## Variables #### Naming variables Variables should be made of lowercase letters only and should be descriptive enough to understand its purpose (even if the variable is longer that preferred). ### Defining variables Any variable should be defined through double quotes ```bash var="value" ``` ### Calling variables Variable should always be called between brackets and double quotes to prevent globbing and word splitting. ```bash echo "${var}" ``` ### Directories Directories are called using LinuxGSM directories variables, or relative to those. Common directory variables can be found in `linuxgsm.sh` and `_default.cfg` . Examples: ```bash mkdir -pv "${servercfgdir}" mkdir -pv "${lgsmdir}/config-default/config-game" du -sh "${rootdir}" 2> /dev/null find "${executabledir}/bin" ``` ## `if` Statements If statements should look like the following ``` if [ "${shortname}" == "csgo" ];then # content fi ``` if statements with multiple options like so ``` if [ "${shortname}" == "csgo" ]||[ "${shortname}" == "css" ]; then # content fi ``` ## Conditional checks ### Syntax * The `if [ statement ]; then` should be a one-liner operation. * Signs comparators like `==`, `lt`, `lt` etc. are preferred to `-eq`, `-le`, `-lt`. * Anything within an if statement must be tabulated one step deeper. Example: ```bash if [ "${test}" == "${var}" ]; then mycheck="true" fi ``` ### Expression Standards Common if expressions LinuxGSM uses. More expressions [here](http://tldp.org/LDP/Bash-Beginners-Guide/html/sect_07_01.html). | Expression | Description | | ---------- | ------------------------------------ | | `-d` | if directory exists | | `! -d` | if directory does not exist | | `-f` | if file exists | | `! -f` | if file does not exist | | `-z` | true if length of string is zero | | `-n` | true if length of string is non-zero | | `-v` | true if the variable exists | {% hint style="danger" %} Do not use `! -z` or `! -n` {% endhint %} There is a distinct difference between -n and -v. -n is used to check is a variable is set and not if it exists\ -v is used to check if a variable exists and not it is set ```bash var="set" if [ -n "${var}" ]; then # Variable is set fi ``` ```bash var="" if [ -z "${var}" ]; then # Variable is not set fi ``` ``` var="" # OR var="set" if [ -v var ]; then # Variable exista fi ``` ``` # var is missing if [ ! -v var ]; then # Variable does not exist fi ``` ## Loops * Loops should be a one liner statement. * Anything within a loop must be tabulated one step deeper. ```bash while [ "${var}" < "${cap}" ]; do echo "This is tabulated" let var=var+1 done ``` ## Comments As English is not always the native language of a developer, comments should use a formal writing style and be straight to the point. If unsure this short formal writing [guide](http://www2.ivcc.edu/rambo/tip_formal_writing_voice.htm) will help. ```bash # Using comments help developers understand complex code, but should be used sparingly. ``` ## Functions * Function should be named starting with `fn_` and using lowercase letters only. * Any recurrent task should be put into a function. * Anything within a function must be tabulated one step deeper. Example: ```bash fn_myfunction(){ echo "This is tabulated" } ``` ## Messages * Messages should be given using core\_messages.sh forms * Additional information messages are given in the form of `echo -e " * Message here"` ## Automated Messages Automated messages are used with any commands that are non-interactive. Examples of this include Start, Stop and Monitor. There are various different alert messages available see [Exit-Codes](broken://pages/-Lgn9gyZzujsevVI68ug) for details. Each automated message starts with `fn_print_dots` to show a process is happening but with no known outcome. `fn_print_dots` ``` [ .... ] Starting fctrserver: ``` Once an outcome of a process is known the message uses an outcome message like `fn_print_ok` or `fn_print_fail` fn\_print\_ok ``` [ OK ] Starting fctrserver: Factorio Server ``` The option of a newline is also available by appending `_nl` for example `fn_print_ok_nl`. This will add a carriage return to the message preventing it being overwritten by the next message. ``` [ OK ] Stopping fctrserver: Graceful: CTRL+c: 2: OK [ .... ] Starting fctrserver: Factorio Server ``` #### Characteristics Interactive messages contain extra detail at the begining of the message that is pre-populated. Full stops must `not` be used with this type of message. ### Interactive Messages Interactive messages are used with any commands that have interactive elements. Examples of this include Install, console and debug. There are various different alert messages available see \[\[Exit-Codes]] for details. ``` Warning! If fctrserver is already running it will be stopped. ``` standard echo commands are normally used to supplement an alert or if an alert is not required. Bullet points can also be used ``` Information! Press "CTRL+b" then "d" to exit console. Warning! Do NOT press CTRL+c to exit. * https://docs.linuxgsm.com/commands/console ``` #### Characteristics Treat interactive messages as a standard sentence. All messages must begin with a capital and end with a full stop --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. 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