shellscript.json

{
	// Place your snippets for shellscript here. Each snippet is defined under a snippet name and has a prefix, body and
	// description. The prefix is what is used to trigger the snippet and the body will be expanded and inserted. Possible variables are:
	// $1, $2 for tab stops, $0 for the final cursor position, and ${1:label}, ${2:another} for placeholders. Placeholders with the
	// same ids are connected.
	// Example:
	// "Print to console": {
	// 	"prefix": "log",
	// 	"body": [
	// 		"console.log('$1');",
	// 		"$2"
	// 	],
	// 	"description": "Log output to console"
	// }

	"Run as root":
	{
		"prefix": "runAsRoot",
		"description": "Runs a script as root if executed by non-root user.",
		"body":
		[
			"# If not run by root, run script as root.",
			"# Options for sudo (choose what is appropriate for this script):",
			"# -i: Short for --login. /root/.profile will be sourced, but /root/.bashrc",
			"#     will exit immediately.",
			"#     Thus, script path variables and \\$PATH containing kalle's scripts' bin dir",
			"#     exported within /root/.profile will be available to this script.",
			"# -E: The environment of the calling user will be preserved; nothing will be sourced.",
			"#     If this is kalle, you will have the script path variables available to this",
			"#     script, but merely root's default \\$PATH.",
			"# If no option is provided, you will merely have root's default \\$PATH and no",
			"# script path variables available to this script.",
			"#",
			"# If this script exports variables before this boilerplate (e. g. when using the",
			"# run-in-screen boilerplate) that shall be available to this script after it has",
			"# been executed by root, you must use -E.",
			"# If you additionally need -i, you must replace ‘sudo [-i|-E]’ below with",
			"# ‘sudo -E bash -l’ because -i and -E are mutually exclusive.",
			"# But by using ‘bash -l’, you get the same effect as with ‘sudo -i’",
			"# (-l is for bash what -i is for sudo).",
			"# If you also use the run-in-screen boilerplate, place it before this one.",
			"((\\$(id -u))) && exec sudo${1| -i , -E , , -E bash -l |}\"$(cd \"\\$(dirname \"\\$0\")\"; pwd)/$(basename \\$0)\" \"$@\""
		]
	},

	"Get absolute path of script":
	{
		"prefix": "scriptAbsPath",
		"description": "Get absolute path of script or link to it no matter how it has been invoked.",
		"body": ["$(cd \\$(dirname  \"\\$0\"); pwd)/\\$(basename \"\\$0\")"]
	},

	"Safely use getopts in a function":
	{
		"prefix": "getoptsInFunction",
		"body":
		[
			"if ((OPTIND != 1)); then",
			"\techo -n \"Error: \\$(basename \\$0): \"",
			"\techo -n \"In function \\${BASH_FUNCNAME[0]}, line \\${BASH_LINENO[0]}: \"",
			"\techo \"OPTIND == \\$OPTIND > 1.\"",
			"\techo 'Your function was about to call getopts,'",
			"\techo -e \"but a previous option processing has not finished yet. Exiting\\n\"",
			"\techo \"----- Call Trace -----\"",
			"",
			"\tlocal line file function i=0",
			"",
			"\twhile caller=\\$(caller \\$i); do",
			"\t\tline=\\$(cut -f 1 -d ' ' <<<\\$caller)",
			"\t\tfile=\\$(cut -f 3 -d ' ' <<<\\$caller)",
			"\t\tfunction=\\$(cut -f 2 -d ' ' <<<\\$caller)",
			"",
			"\t\tif [[ \\$function != source ]]; then",
			"\t\t\tfunction=\"(function: \\$function)\"",
			"\t\telse",
			"\t\t\tfunction=\"(\\$function)\"",
			"\t\tfi",
			"",
			"\t\techo \"\\$file Line: \\$line \\$function\"",
			"",
			"\t\t((i++))",
			"\tdone",
			"",
			"\texit 1",
			"fi",
			"",
			"local opt",
			"",
			"while getopts '$1' opt; do",
			"\tcase \\$opt in",
			"\t\t$2)",
			"\t\t\t$0",
			"\t\t\t;;",
			"\tesac",
			"done",
			"",
			"# Remove option args from positional parameters.",
			"# N.B.: After reading all option args, \\$OPTIND is the index of the first",
			"# non-option arg, thus \\$((OPTIND - 1)) is the number of option args.",
			"shift \\$((OPTIND - 1))",
			"",
			"# Reset \\$OPTIND to indicate we have finished using getopts.",
			"OPTIND=1"
		]
	},

	"Use getopts in a standalone script":
	{
		"prefix": "getoptsInStandaloneScript",
		"body":
		[
			"local opt\n",
			"while getopts '$1' opt; do",
			"\tcase \\$opt in",
			"\t\t$2)",
			"\t\t\t$0",
			"\t\t\t;;",
			"\tesac",
			"done\n",
			"# Remove option args from positional parameters.",
			"# N.B.: After reading all option args, \\$OPTIND is the index of the first",
			"# non-option arg, thus \\$((OPTIND - 1)) is the number of option args.",
			"shift \\$((OPTIND - 1))\n"
		]
	},

	// See "Prompt user for choice (Yn)" in jsonc.json for a version for usage within a shell Task.
	"Prompt user for choice (Yn)":
	{
		"prefix": "prompt_choice_Yn",
		"body":
		[
			"echo -en \"\\e[1m\\e[97m${1:promptText}\\e[0m \\e[97m[Y/n] \\e[1m\"\n",
			"command -v tput >/dev/null && haveTput=1",
			"((haveTput)) && tput sc\n",
			"while true; do",
			"read -n 1 ans\n",
			"\tcase \\$ans in",
			"\t\t'')",
			"\t\t\techo -en \"\\e[0m\"",
			"\t\t\t;;&",
			"\t\t[yYnN])",
			"\t\t\techo -e \"\\e[0m\"",
			"\t\t\t;;&",
			"\t\t[yY]|'')",
			"\t\t\t${2:commandsY}",
			"",
			"\t\t\tbreak",
			"\t\t\t;;",
			"\t\t[nN])",
			"\t\t\t${3:commandsN}",
			"",
			"\t\t\tbreak",
			"\t\t\t;;",
			"\t\t*)",
			"\t\t\t((haveTput)) && tput rc && tput el # Restore cursor pos and clear to end of line (see man terminfo).",
			"\t\t\t;;",
			"\tesac",
			"done",
		]
	},

	// See "Prompt user for choice (yN)" in jsonc.json for a version for usage within a shell Task.
	"Prompt user for choice (yN)":
	{
		"prefix": "prompt_choice_yN",
		"body":
		[
			"echo -en \"\\e[1m\\e[97m${1:promptText}\\e[0m \\e[97m[y/N] \\e[1m\"\n",
			"command -v tput >/dev/null && haveTput=1",
			"((haveTput)) && tput sc\n",
			"while true; do",
			"read -n 1 ans\n",
			"\tcase \\$ans in",
			"\t\t'')",
			"\t\t\techo -en \"\\e[0m\"",
			"\t\t\t;;&",
			"\t\t[yYnN])",
			"\t\t\techo -e \"\\e[0m\"",
			"\t\t\t;;&",
			"\t\t[yY])",
			"\t\t\t${2:commandsY}",
			"",
			"\t\t\tbreak",
			"\t\t\t;;",
			"\t\t[nN]|'')",
			"\t\t\t${3:commandsN}",
			"",
			"\t\t\tbreak",
			"\t\t\t;;",
			"\t\t*)",
			"\t\t\t((haveTput)) && tput rc && tput el # Restore cursor pos and clear to end of line (see man terminfo).",
			"\t\t\t;;",
			"\tesac",
			"done",
		]
	},

	"Run command with nullglob (single line)":
	{
		"prefix": "runWithNullglobSingleLine",
		"description":
		[
			"Runs the specified command with nullglob.",
			"Leaving nullglob on for the rest of a script can cause strange side effects (but I don't remember them)."
		],
		"body":
		[
			"shopt -s nullglob; ${1:command}; shopt -u nullglob",
		]
	},
	"Run command with nullglob":
	{
		"prefix": "runWithNullglob",
		"description":
		[
			"Runs the specified command with nullglob.",
			"Leaving nullglob on for the rest of a script can cause strange side effects (but I don't remember them)."
		],
		"body":
		[
			"shopt -s nullglob",
			"${1:command}",
			"shopt -u nullglob",
		]
	},

	"Test if an executable is available":
	{
		"prefix": "testIfExecutableAvailable",
		"description": "Test if the supplied executable exists in a dir contained in $PATH.",
		"body":
		[
			"command -v ${1:executableName} >/dev/null "
		]
	},

	// See "Prompt user to press any key (escaped)" in jsonc.json for a version for usage within a shell Task.
	"Prompt user to press any key":
	{
		"prefix": "prompt_pressAnyKey",
		"description": "Wait until any key is pressed.",
		"body":
		[
			"echo -en \"\\n\\e[1m\\e[97mPress any key to close the window.\"; read -n 1"
		]
	},

	"Repeat string":
	{
		"prefix": "repeatString",
		"body":
		[
			"((${2:repeatTimes} > 0)) && printf \"%.0s${1:string}\" \\$(seq 1 ${2:repeatTimes})"
		]
	},

	"Repeat string in command substitution":
	{
		"prefix": "repeatStringCmdSubst",
		"body":
		[
			"$( ((${2:repeatTimes} > 0)) && printf \"%.0s${1:string}\" \\$(seq 1 ${2:repeatTimes}) )"
		]
	},

	"Access global var with unique name via local nameref in lib (function)":
	{
		"prefix": "globalVarAsLocalNameref_func",
		"description":
		[
			"",
			"Insert the snippet \"Access global var with unique name via local nameref in lib (command)\"",
			"into a function to create a variable."
		],
		"body":
		[
			"# Usage: eval $(globalVarAsNameref <varName>) (within a function in a sourced script)",
			"#",
		]
	},

	"Access global var with unique name via local nameref in lib (command)":
	{
		"prefix": "globalVarAsLocalNameref_command",
		"description":
		[
			"The command to create a global variable with unique name that can be accessed via local nameref.",
			"",
			"Insert the snippet with prefix \"globalVarAsLocalNameref_source\" to use this."
		],
		"body":
		[
			"eval $(globalVarAsLocalNameref ${1:varName})"
		]
	},

	"Access global var with unique name via local nameref in lib (source)":
	{
		"prefix": "globalVarAsLocalNameref_source",
		"description":
		[
			"This sources a lib containing a function that can be used to create a global variable with unique",
			"name accessible via local nameref <varName>.",
			"",
			"Use if you need to persist data across multiple invocations of a function or share data between",
			"different functions within a lib script; just the typical use case for a variable at script level.",
			"",
			"The global variable will be accessible via a short, convenient name whereas its true name will be",
			"_<varName>_<basename of sourcing script with - and . replaced with _, if any>,",
			"so you may use the same <varName> in multiple libs sourced by the same script without collisions.",
			"",
			"Insert the snippet with prefix \"globalVarAsLocalNameref_command\" into a function to create a variable."
		],
		"body":
		[
			". \"$scriptsCommonInclude/libglobal-var-as-local-nameref\"",
		]
	},

	"Quoted array elements":
	{
		"prefix": "arrayElementsQuoted",
		"body":
		[
			"\"\\${${1:arrayName}[@]}\""
		]
	},

	"Number of array elements":
	{
		"prefix": "arrayElementCount",
		"body":
		[
			"\\${#${1:arrayName}[@]}"
		]
	},

	"Get file extension":
	{
		"prefix": "getFileExt",
		"body":
		[
			"\\${${1:path}##*.}",
		]
	},

	"function error":
	{
		"prefix": "funcErr",
		"body":
		[
			"# Prints an error message and exits with value 1.",
			"# Arg: A string explaining the reason.",
			"function error",
			"{",
			"\tlocal reason=\\$1",
			"",
			"\tlocal light_red='\\e[91m' bold='\\e[1m' norm='\\e[0m'",
			"\tlocal msg=\"\\$bold\\${light_red}Error:\\$norm\\$light_red \\$reason\\$bold\"",
			"",
			"\tif [[ \\$reason == *. ]]; then",
			"\t\tmsg+=' Exiting.'",
			"\telif [[ \\$reason == *, ]]; then",
			"\t\tmsg+=' exiting.'",
			"\telse",
			"\t\tmsg+='. Exiting.'",
			"",
			"\t\techo \"Warning: function error: Supplied reason doesn't end with dot or comma.\"",
			"\t\techo -e \"I have appended a dot for you. Append the right punctuation mark to silence this warning.\\n\"",
			"\tfi",
			"",
			"\techo -e \"\\$msg\\$norm\"",
			"",
			"\texit 1",
			"}"
		]
	},

	"Shell script doc comment quotes":
	{
		"prefix": "docQuotes",
		"description":
		[
			"Inserts a pair of quotes (‘’, also used e. g. in the official Bash documentation)",
			"suitable to quote code examples in a comment,",
			"e. g. ‘foo='bar baz'’ or ‘echo -e \"foo\\n\"’.",
			"You see, neither '' nor \"\" would be appropriate."
		],
		"body": "‘$1’"
	},

	"Multiline captures (3 captures per line, input from variable)":
	{
		"prefix": "multilineCaptures3Var",
		"body":
		[
			"readarray -t captures <<<\\$(sed -En 's/${2:capRegexp}/\\1\\n\\2\\n\\3/p' <<<\\$${1:inputVarName})",
			"",
			"for ((i = 0; i < \\${#captures[@]}; i += 3)); do",
			"\t${3:cap1}=\\${captures[i]}",
			"\t${4:cap2}=\\${captures[i + 1]}",
			"\t${5:cap3}=\\${captures[i + 2]}",
			"",
			"\t$0",
			"done"
		]
	},

	"Multiline captures (3 captures per line, input from command)":
	{
		"prefix": "multilineCaptures3Cmd",
		"body":
		[
			"readarray -t captures <<<\\$(${1:command} | sed -En 's/${1:capRegexp}/\\1\\n\\2\\n\\3/p')",
			"",
			"for ((i = 0; i < \\${#captures[@]}; i += 3)); do",
			"\t${3:cap1}=\\${captures[i]}",
			"\t${4:cap2}=\\${captures[i + 1]}",
			"\t${5:cap3}=\\${captures[i + 2]}",
			"",
			"\t$0",
			"done"
		]
	},

	"Index-based iteration over array elements":
	{
		"prefix": "arrayIterIndexBased",
		"body":
		[
			"for ((i = 0; i < \\${#${1:elementVarName}s[@]}; i++)); do",
			"\t${1:elementVarName}=\\${${1:elementVarName}s[i]}",
			"",
			"\t$0",
			"done"
		]
	},

	"function shiftArray":
	{
		"prefix": "funcShiftArray",
		"body":
		[
			"# Args: <array name> <n>",
			"function shiftArray",
			"{",
			"\tlocal -n _array_=\\$1",
			"\tlocal i n=\\$2",
			"",
			"\tfor ((i = 0; i < ${#_array_[@]} - n; i++)); do",
			"\t\tarray_[i]=${_array_[i + n]}",
			"\tdone",
			"",
			"\tfor ((i = 0; i < n; i++)); do unset \"_array_[-1]\"; done",
			"}"
		]
	},

	"function removeArrayElement":
	{
		"prefix": "funcRemoveArrayElement",
		"body":
		[
			"# Args: <arrayName> <i>",
			"function removeArrayElement",
			"{",
			"\tlocal -n _array_=\\$1",
			"",
			"\tfor ((i = \\$2; i < \\${#_array_[@]} - 1; i++)); do",
			"\t\t_array_[i]=${_array_[i + 1]}",
			"\tdone",
			"",
			"\tunset _array_[-1]",
			"}"
		]
	},

	"Array element":
	{
		"prefix": "arrayElement",
		"body":
		[
			"\\${${1:arrayName}[${2:subscript}]}"
		]
	},

	"Clear current line":
	{
		"prefix": "clearCurrentLine",
		"body":
		[
			"tput cr; tput el # Carriage return and clear to end of line (see man terminfo)"
		]
	},
}