#!/bin/bash -e

set -o errexit -o pipefail # errexit in case caller's #! line missing -e

if test ! "$_util_sh_include_guard_utils"; then

_util_sh_include_guard_utils=1

isset() { declare -p "$1" &>/dev/null; }

realpath() { readlink -f -- "$1"; }

str2varname() { echo "${1//[^a-zA-Z0-9_]/_}"; }

include_guard_var() { str2varname "$(realpath "$1")"; }

self_not_included() # usage: if self_not_included; then ... fi

{

	test $# -ge 1 || set -- "${BASH_SOURCE[1]}"

	local include_guard="$(include_guard_var "$1")"

	alias self_being_included=false

	! isset "$include_guard" && \

	{ eval "$include_guard"=1; alias self_being_included=true; }

}

# to load newly-defined aliases for use in functions in the same file:

## fi # load new aliases

## if self_being_included; then

# this is needed because aliases defined inside an if statement are not

# available inside that if statement

fi

if self_not_included "${BASH_SOURCE[0]}"; then

#### options

shopt -s expand_aliases

# allow setting vars in the last command of a pipeline

shopt -s lastpipe 2>/dev/null || true # ignore errors if not supported (on Mac)

#### stubs

__caller_indent='log_indent="$log_indent$log_indent_step"'

alias caller_indent="$__caller_indent"

alias indent="declare $__caller_indent"

function echo_func() { :; }

alias echo_func='"echo_func" "$FUNCNAME" "$@" && indent || true'

function echo_run() { :; }

alias echo_run='"echo_run" ' # last space alias-expands next word

# auto-echo common external commands

for cmd in env rm which; do alias "$cmd=echo_run $cmd"; done; unset cmd

echo_builtin() { :; }

function echo_vars() { :; }

#### debugging

dp() { echo "$@" >&2; } # usage: pv var... # debug-prints message

#### logic

not() { ! "$@"; } # usage: wrapper_cmd not wrapped_cmd... # inverts exit status

#### vars

alias local_array='declare'

	# `local` does not support arrays in older versions of bash

	# don't need -a because that it's an array is autodetected by the ()

set_var() { eval "$1"'="$2"'; }

set_default() { if ! isset "$1"; then set_var "$@"; fi; }

set_inv() { set_var no_"$1" "$(test "${!1}" || echo 1)"; }

# usage: local var=...; local_inv

alias local_inv=\

'declare "no_$var=$(test "${!var}" || echo 1)"; echo_vars no_$var'

unexport() { export -n "$@"; }

	# `declare +x` won't work because it defines the var if it isn't set

alias local_export='declare -x' # combines effects of local and export

alias export_array='declare -x'

	# `export` does not support arrays in older versions of bash

	# don't need -a because that it's an array is autodetected by the ()

# to make export only visible locally: local var="$var"; export var

# within cmd: var="$var" cmd...

get_prefix_vars() { : "${prefix:?}"; eval echo '${!'$prefix'*}'; }

# usage: local prefix=..._; import_vars

# when used inside another alias 2+ levels deep, *must* be run inside a function

alias import_vars="$(cat <<'EOF'

: "${prefix:?}"

declare src_var dest_var

for src_var in $(get_prefix_vars); do

	dest_var="${src_var#$prefix}"

	declare "$dest_var=${!dest_var-${!src_var}}"; echo_vars "$dest_var"

done

EOF

)"

#### caching

## shell-variable-based caching

# usage: local cache_key=...; load_cache; \

# if ! cached; then save_cache value || return; fi; echo_cached_value

# cache_key for function inputs: "$(declare -p kw_param...) $*"

alias load_cache='declare cache_var="$(str2varname "${FUNCNAME}___$cache_key")"'

alias cached='isset "$cache_var"'

alias save_cache='set_var "$cache_var"'

alias echo_cached_value='echo "${!cache_var}"'

clear_cache() # usage: func=... clear_cache

{ : "${func:?}"; unset $(prefix="${func}___" get_prefix_vars); }

fi # load new aliases

if self_being_included; then

#### aliases

unalias() { builtin unalias "$@" 2>&- || true; } # no error if undefined

# usage: alias alias_='var=value run_cmd '

function run_cmd() { "$@"; }

alias run_cmd='"run_cmd" ' # last space alias-expands next word

alias_append() { eval "$(alias "$1")"'"$2"';} #usage: alias_append alias '; cmd'

#### commands

is_callable() { type -t "$@" >/dev/null; }

is_dot_script() { echo_func; test "${BASH_LINENO[${#BASH_LINENO[@]}-1]}" != 0; }

require_dot_script() # usage: require_dot_script || return

{

	echo_func

	if ! is_dot_script; then # was run without initial "."

		echo "usage: . $top_script (note initial \".\")"|fold -s >&2

		return 2

	fi

}

sys_cmd_path() { echo_func; echo_builtin command -p which "$1"|echo_stdout; }

# makes command in $1 a system command

# allows running a system command of the same name as the script

alias cmd2sys="$(cat <<'EOF'

declare _1="$1"; shift

_1="$(indent; log++ sys_cmd_path "$_1")" || return

set -- "$_1" "$@"

EOF

)"

fi # load new aliases

if self_being_included; then

sys_cmd() { cmd2sys; command "$@"; } # usage: sys_cmd cmd... # runs system cmd

	# allows running a system command of the same name as the script

#### functions

kw_params() # usage: func() { kw_params param_var...; }; ...; param_var=... cmd

# removes keyword-param-only vars from the environment

{ unexport "$@"; }

# usage: cmd=... foreach_arg

function foreach_arg()

{

	echo_func; kw_params cmd; : "${cmd:?}"

	local a; for a in "$@"; do

		a="$(log++ echo_run "$cmd" "$a")" || return; args+=("$a")

	done

	echo_vars args

}

alias foreach_arg='"foreach_arg" "$@"; set -- "${args[@]}"; unset args'

alias self_name='echo "${FUNCNAME%%__*}"' # usage: "$(self_name)"

alias self='command "$(self_name)"' # usage: wrapper() { self ...; }

alias self_sys='sys_cmd "$(self_name)"' # wrapper() { self_sys ...; }

pv() { declare -p "$@" >&2; } # usage: pv var... # debug-prints var(s)

pf() { declare -f "$@" >&2; } # usage: pf function # debug-prints func decl

all_funcs() # usage: for func in $(all_funcs); do ...; done # all declared funcs

{ declare -F|while read -r line; do echo -n "${line#declare -f } "; done; }

#### exceptions

# usage: cmd || { save_e; ...; rethrow; }

alias export_e='e=$?'

# **WARNING**: if using this after a command that might succeed (rather than

# only upon error), you must `unset e` before the command

# idempotent: also works if save_e already called

alias save_e='# idempotent: use $e if the caller already called save_e

declare e_=$?;

declare e="$(if test "$e_" = 0; then echo "${e:-0}"; else echo "$e_"; fi)"'

alias rethrow!='return "$e"'

	# can't use `(exit "$e")` because a bug in bash prevents subshells from

	# triggering errexit (would need to append `|| return` for it to work)

alias rethrow_exit!='exit "$e"'

alias rethrow='{ if test "$e" != 0; then rethrow!; fi; }'

alias rethrow_exit='{ if test "$e" != 0; then rethrow_exit!; fi; }'

alias rethrow_subshell='rethrow_exit'

fi # load new aliases

if self_being_included; then

# usage: try cmd...; ignore_e status; if catch status; then ...; fi; end_try

alias prep_try='declare e=0' # last space alias-expands next word

# usage: ...; try cmd... # *MUST* be at beginning of statement

#     OR prep_try; wrapper "try" cmd...

function try() { benign_error=1 "$@" || { export_e; true; }; }

alias try='prep_try; "try" ' # last space alias-expands next word

catch() { test "$e" = "${1:-0}" && e=0; } # also works w/ $1=''

ignore_e() { catch "$@" || true; } # also works w/ $1=''

alias end_try='rethrow'

alias end_try_subshell='rethrow_subshell'

ignore() { save_e; ignore_e "$@"; rethrow; } # usage: try cmd || ignore status

### signals

sig_e() { echo $(( 128+$(kill -l "$1") )); } # usage: sig_e SIGINT, etc.

ignore_sig() { ignore "$(sig_e "$1")"; }

# usage: piped_cmd cmd1...|cmd2... # cmd2 doesn't read all its input

function piped_cmd() { "$@" || ignore_sig SIGPIPE; }

alias piped_cmd='"piped_cmd" ' # last space alias-expands next word

fi # load new aliases

if self_being_included; then

#### integers

let!() { let "$@" || true; } # always returns true; safe to use for setting

	# "If the last ARG evaluates to 0, let returns 1" (`help let`)

bool2int() { try test ! "$1"; echo "$e"; } # empty->0; non-empty->1

int2exit() { (( "$1" != 0 )); }

exit2bool() { if (( $? == 0 )); then echo 1; fi } # 0->non-empty; !=0->empty

#### floats

int_part() { echo "${1%%.*}"; }

dec_suffix() { echo "${1#$(int_part "$1")}"; }

round_down() { int_part "$1"; }

float+int() { echo "$(($(int_part "$1")+$2))$(dec_suffix "$1")"; }

float_set_min() { if (($(int_part $1) >= $2)); then echo $1; else echo $2; fi; }

#### strings

starts_with() { test "${2#$1}" != "$2"; } # usage: starts_with pattern str

match_prefix() # usage: match_prefix pattern str

{ if starts_with "$1" "$2"; then echo "${2%${2#$1}}"; fi }

rm_prefix() { echo "${2#$1}"; } # usage: rm_prefix pattern str

repeat() # usage: str=... n=... repeat

{

	: "${str?}" "${n:?}"; local result= n="$n" # n will be modified in function

	for (( ; n > 0; n-- )); do result="$result$str"; done

	echo "$result"

}

# usage: outer_cmd $sed_cmd ...

sed_cmd="env LANG= sed -`case "$(uname)" in Darwin) echo El;; *) echo ru;;esac`"

	# LANG: avoid invalid UTF-8 "illegal byte sequence" errors when LANG=*.UTF-8

	# -l: line buffered / -u: unbuffered

alias sed="$sed_cmd"

	# can't be function because this causes segfault in redir() subshell when

	# used with make.sh make() filter

fi # load new aliases

if self_being_included; then

rtrim() { log_local; log+ 3; sed 's/[[:space:]]+$//' <<<"$1"; }

#### arrays

echo1() { echo "$1"; } # usage: echo1 values...

esc_args() # usage: array=($(log++; prep_env... (eg. cd); esc_args args...))

{ local arg; for arg in "$@"; do printf '%q ' "$arg"; done; }

# usage: split delim str; use ${parts[@]}

function split() { local IFS="$1"; parts=($2); echo_vars parts; }

	# no echo_func because used by log++

alias split='declare parts; "split"'

join() { local IFS="$delim"; echo "$*"; } # usage: delim=char join elems...

reverse() # usage: array=($(reverse args...))

{

	local i

	for (( i=$#; i > 0; i-- )); do printf '%q ' "${!i}"; done

}

contains() # usage: contains value in_array...

{

	local value="$1"; shift

	local elem

	for elem in "$@"; do if test "$elem" = "$value"; then return 0; fi; done

	return 1

}

is_array() # handles unset vars (=false)

{

	isset "$1" || return 1

	local decl; decl="$(declare -p "$1")" || return; echo_vars decl

	starts_with 'declare -a' "$decl" # also matches -ax

}

#### text

fi # load new aliases

if self_being_included; then

nl='

'

# usage: split_lines str; use ${lines[@]}

function split_lines() { split "$nl" "$1"; lines=("${parts[@]}"); }

	# no echo_func because used by log++

alias split_lines='declare lines; "split_lines"'

#### paths

strip/() { echo "${1%/}"; } # strips trailing /s

wildcard/() # usage: array=($(log++; [cd ...;] wildcard/ unquoted_pattern...))

{ cmd=strip/ foreach_arg; esc_args "$@"; }

wildcard.() # usage: array=($(log++; [cd ...;] wildcard. unquoted_pattern...))

# currently only removes . .. at beginning of list

{

	set -- $(wildcard/ "$@") # first strip trailing /s

	local to_rm=(. ..)

	local item

	if contains "$1" "${to_rm[@]}"; then

		shift

		if contains "$1" "${to_rm[@]}"; then shift; fi

	fi

	esc_args "$@"

}

#### streams

pipe_delay() # usage: cmd1 | { pipe_delay; cmd2; }

{ sleep 0.1; } # s; display after leading output of cmd1

#### verbose output

err_fd=2 # stderr

usage() { echo "Usage: $1" >&2; return 2; }

### log++

log_fd=2 # initially stderr

if test "$explicit_errors_only"; then verbosity=0; fi # hide startup logging

# set verbosity

if isset verbose; then : "${verbosity:=$(bool2int "$verbose")}"; fi

if isset vb; then : "${verbosity:=$vb}"; fi

: "${verbosity=1}" # default

: "${verbosity:=0}" # ensure non-empty

export verbosity # propagate to invoked commands

is_outermost="$(! isset log_level; exit2bool)" # if util.sh env not yet set up

# set log_level

: "${log_level=$(( ${#PS4}-1 ))}" # defaults to # non-space symbols in PS4

export log_level # propagate to invoked commands

export PS4 # follows log_level, so also propagate this

verbosity_int() { round_down "$verbosity"; }

# verbosities (and `make` equivalents):

# 0: just print errors. useful for cron jobs.

#    vs. make: equivalent to --silent, but suppresses external command output

# 1: also external commands run. useful for running at the command line.

#    vs. make: not provided (but sorely needed to avoid excessive output)

# 2: full graphical call tree. useful for determining where error occurred.

#    vs. make: equivalent to default verbosity, but with much-needed indents

# 3: also values of kw params and variables. useful for low-level debugging.

#    vs. make: not provided; need to manually use $(error $(var))

# 4: also variables in util.sh commands. useful for debugging util.sh.

#    vs. make: somewhat similar to --print-data-base

# 5: also variables in logging commands themselves. useful for debugging echo_*.

#    vs. make: not provided; need to search Makefile for @ at beginning of cmd

# 6+: not currently used (i.e. same as 5)

# definition: the log_level is the minimum verbosity needed to display a message

# for messages that use can_log(), the log_level starts with *1*, not 0

# for unfiltered messages, the log_level is 0 (i.e. still output at verbosity=0)

# to view a message's log_level, count the # of + signs before it in the output

alias log_local='declare PS4="$PS4" log_level="$log_level"'

fi # load new aliases

if self_being_included; then

# usage: in func:      log_local; log++; ...

#        outside func: log_local; log++; ...; log--

#        before cmd:   log++ cmd  OR  log+ num cmd  OR  log++ log++... cmd

# with a cmd, assignments are applied just to it, so log_local is not needed

# without a cmd, assignments are applied to caller ("$@" expands to nothing)

# "${@:2}" expands to all of $@ after *1st* arg, not 2nd ($@ indexes start at 1)

log:() # sets explicit log_level

{

	if test $# -gt 1; then log_local; fi # if cmd, only apply assignments to it

	# no local vars because w/o cmd, assignments should be applied to caller

	log_level="$1"

	PS4="$(str="${PS4:0:1}" n=$((log_level-1)) repeat)${PS4: -2}"

	"${@:2}"

}

log+() { log: $((log_level+$1)) "${@:2}"; }

log-() { log+ "-$1" "${@:2}"; }

# no log:/+/- alias needed because next word is not an alias-expandable cmd

function log++() { log+ 1 "$@"; }

function log--() { log- 1 "$@"; }

function log!() { log: 0 "$@"; } # force-displays next log message

alias log++='"log++" ' # last space alias-expands next word

alias log--='"log--" ' # last space alias-expands next word

alias log!='"log!" ' # last space alias-expands next word

verbosity_min() # usage: verbosity_min {<min>|''}

# WARNING: '' is a special value that causes $verbosity to be overwritten to ''

{ if test ! "$1" -o "$(verbosity_int)" -lt "$1"; then verbosity="$1"; fi; }

alias verbosity_min='declare verbosity="$verbosity"; "verbosity_min"'

# usage: (verbosity_compat; cmd)

function verbosity_compat()

{ echo_func; if ((verbosity == 1)); then unset verbosity; fi; }

alias verbosity_compat='declare verbosity="$verbosity"; "verbosity_compat"'

# indent for call tree. this is *not* the log_level (below).

: "${log_indent_step=| }" "${log_indent=}"

export log_indent_step log_indent # propagate to invoked commands

# see indent alias in stubs

fi # load new aliases

if self_being_included; then

can_log() { test "$log_level" -le "$(verbosity_int)"; }

	# verbosity=0 turns off all logging

can_highlight_msg() { test "$log_level" -le 1; }

highlight_msg() # usage: [format=...] highlight_msg msg

# format: the # in xfree86.org/current/ctlseqs.html#Character_Attributes

{

	kw_params format; local format="${format-1}" # bold

	local highlight="$(test "$format" && can_highlight_msg; exit2bool)"

	echo "${highlight:+[${format}m}$1${highlight:+}"

}

log_line!() # highlights log_level 1 messages to stand out against other output

{ echo "$log_indent$PS4$(highlight_msg "$1")" >&"$log_fd"; }

log_msg!()

{ split_lines "$1"; local l; for l in "${lines[@]}"; do log_line! "$l"; done; }

log() { if can_log; then log_msg! "$@"; fi; }

log_custom() # usage: symbol=... log_custom msg

{ log_indent="${log_indent//[^ ]/$symbol}" PS4="${PS4//[^ ]/$symbol}" log "$@";}

bg_r='101;97' # red background with white text

log_err() { symbol='#' format="$bg_r" log_fd="$err_fd" log! log_custom " $1 ";}

log_info() { symbol=: log_custom "$@"; }

log_hint!() { format=7 log_info " $1 "; }

log_hint() # usage: cmd || [benign_error=1] log_hint msg [|| handle error]

# msg only displayed if not benign error

{ kw_params benign_error; if test ! "$benign_error"; then log_hint! "$@"; fi; }

die() # usage: cmd || [type=...] die msg # msg can use $? but not $()

{ save_e; kw_params type; "log_${type:-err}" "$1"; rethrow; }

die_e() # usage: cmd || [benign_error=1] die_e [|| handle error]

{

	save_e; kw_params benign_error

	if test "$benign_error"; then log_local; log++; fi

	type="${benign_error:+info}" die "command exited with \

$(if test "$benign_error"; then echo status; else echo error; fi) $e"

	rethrow

}

die_error_hidden() # usage: cmd || verbosity_min=# die_error_hidden [|| ...]

{

	save_e; kw_params verbosity_min; : "${verbosity_min:?}"

	echo_vars verbosity

	if test "$(verbosity_int)" -lt "$verbosity_min"; then

		log_hint 'to see error details, prepend `vb='"$verbosity_min"'` to the command'

	fi

	rethrow

}

#### functions

func_exists() { declare -f "$1" >/dev/null; }

copy_func() # usage: from=... to=... copy_func

# $to must not exist. to get around the no-clobber restriction, use `unset -f`.

{

	: "${from:?}" "${to:?}"

	func_exists "$from" || die "function does not exist: $from"

	! func_exists "$to" || die "function already exists: $to"

	local from_def="$(declare -f "$from")"

	eval "$to${from_def#$from}"

}

func_override() # usage: func_override old_name__suffix

{ from="${1%__*}" to="$1" copy_func; }

ensure_nested_func() # usage: func__nested_func() { ensure_nested_func; ... }

{

	local nested_func="${FUNCNAME[1]}"

	local func="${nested_func%%__*}"

	contains "$func" "${FUNCNAME[@]}" || \

		die "$nested_func() must be used by $func()"

}

#### paths

# cache realpath

: "${realpath_cache=}" # default off because slower than without

if test "$realpath_cache"; then

func_override realpath__no_cache

realpath() # caches the last result for efficiency

{

	local cache_key="$*"; load_cache

	if ! cached; then save_cache "$(realpath__no_cache "$@")" || return; fi

	echo_cached_value

}

fi

rel_path() # usage: base_dir=... path=... rel_path

{

	kw_params base_dir path

	: "${base_dir:?}" "${path:?}"

	local path="$path/" # add *extra* / to match path when exactly = base_dir

	path="${path#$base_dir/}" # remove prefix shared with base_dir

	path="${path%/}" # remove any remaining extra trailing /

	if test ! "$path"; then path=.; fi # ensure non-empty

	echo_vars path

	echo "$path"

}

cd -P . # expand symlinks in $PWD so it matches the output of realpath

# do before setting $top_script_abs so realpath has less symlinks to resolve

canon_rel_path() # usage: [base_dir=...] canon_rel_path path

{

	kw_params base_dir; local base_dir="${base_dir-$PWD}"

	base_dir="$(realpath "$base_dir")" || return

	local path; path="$(realpath "$1")" || return

	rel_path

}

canon_dir_rel_path() # usage: [base_dir=...] canon_dir_rel_path path

# if the path is a symlink, just its parent dir will be canonicalized

{

	kw_params base_dir; local base_dir="${base_dir-$PWD}"

	base_dir="$(realpath "$base_dir")" || return

	local path; path="$(realpath "$(dirname "$1")")/$(basename "$1")" || return

	rel_path

}

# makes $1 a canon_rel_path if it's a filesystem path

alias cmd2rel_path="$(cat <<'EOF'

if test "$(type -t "$1")" = file && test -e "$1"; then # not relative to PATH

	declare _1="$1"; shift

	_1="$(log++ canon_rel_path "$_1")" || return

	set -- "$_1" "$@"

fi

EOF

)"

# usage: path_parents path; use ${dirs[@]} # includes the path itself

function path_parents()

{

	echo_func; local path="$1" prev_path=; dirs=()

	while test "$path" != "$prev_path"; do

		prev_path="$path"

		dirs+=("$path")

		path="${path%/*}"

	done

}

alias path_parents='declare dirs; "path_parents"'

#### verbose output

### command echoing

alias echo_params='log "$*"'

fi # load new aliases

if self_being_included; then

echo_cmd() { echo_params; }

function echo_run() { echo_params; "$@"; }

# see echo_run alias after stub

echo_builtin() { echo_run builtin "$@"; } # usage: echo_builtin builtin_cmd...

echo_eval() { echo_params; builtin eval "$@"; }

# usage: redirs=(...); [cmd_name_log_inc=#] echo_redirs_cmd

function echo_redirs_cmd()

{

	local cmd_name_log_inc="${cmd_name_log_inc-0}"

	# print <>file redirs before cmd, because they introduce it

	log+ "$cmd_name_log_inc" echo_cmd "$@" $(

		set -- "${redirs[@]}" # operate on ${redirs[@]}

		while test "$#" -gt 0 && starts_with '[<>][^&]' "$1"

		do log "$1 \\"; shift; done # log() will run *before* echo_cmd itself

		echo "$@"

	)

}

alias echo_redirs_cmd='"echo_redirs_cmd" "$@"'

## vars

echo_vars() # usage: echo_vars var... # only prints vars that are defined

{

	log_local; log+ 2

	if can_log; then

		local var

		for var in "${@%%=*}"; do

			if isset "$var"; then log "$(declare -p "$var")"; fi

		done

	fi

}

echo_export() { builtin export "$@"; echo_vars "$@"; }

alias export="echo_export" # automatically echo env vars when they are set

func_override kw_params__lang

kw_params() { kw_params__lang "$@"; echo_vars "$@"; } # echo all keyword params

## functions

# usage: local func=...; set_func_loc; use $file, $line

alias set_func_loc="$(cat <<'EOF'

: "${func:?}"

local func_info="$(shopt -s extdebug; declare -F "$func")" # 'func line file'

func_info="${func_info#$func }"

local line="${func_info%% *}"

local file="${func_info#$line }"

EOF

)"

fi # load new aliases

if self_being_included; then

func_loc() # gets where function declared in the format file:line

{

	local func="$1"; set_func_loc

	file="$(canon_rel_path "$file")" || return

	echo "$file:$line"

}

# usage: func() { [minor=1] echo_func; ... }

function echo_func()

# usage: "echo_func" "$FUNCNAME" "$@" && indent || true

# exit status: whether function call was echoed

{

	log_local; log++; can_log || return

	local func="$1"; shift

	local loc; loc="$(log++ func_loc "$func")" || return

	echo_cmd "$loc" "$func" "$@"

}

# see echo_func alias after stub

fi # load new aliases

if self_being_included; then

#### streams

fd_exists() { (: <&"$1") 2>/dev/null; }

require_fd_not_exists() # usage: require_fd_not_exists fd || return 0

{ ! fd_exists "$1" || type=info die "fd $1 already exists, skipping"; }

set_fds() # usage: set_fds redirect...

# WARNING: does not currently support redirecting an fd to itself (due to bash

# bug that requires the dest fd to be closed before it can be reopened)

{

	echo_func

	# add #<>&- before every #<>&# reopen to fix strange bash bug

	local redirs=() i

	for i in "$@"; do

		# remove empty redirects resulting from using `redirs= cmd...` to clear

		# the redirs and then using $redirs as an array

		if test "$i"; then

			local redir_prefix="$(match_prefix '*[<>]' "$i")"

			local dest="$(        rm_prefix    '*[<>]' "$i")"

			if test "$dest" && ! starts_with '&' "$dest"; then # escape dest

				i="$redir_prefix$(printf %q "$dest")"

			fi

			if test "$redir_prefix"; then redirs+=("$redir_prefix&-"); fi

			redirs+=("$i")

		fi

	done

	set -- "${redirs[@]}"

	if (($# > 0)); then echo_eval exec "$@"; fi

}

fd_set_default() # usage: fd_set_default 'dest[<>]src'

{

	echo_func

	local dest="${1%%[<>]*}"

	require_fd_not_exists "$dest" || return 0

	set_fds "$1"

}

stdout2fd() # usage: fd=# stdout2fd cmd...

{

	echo_func; kw_params fd; : "${fd?}"

	if test "$fd" != 1; then local redirs=(">&$fd" "${redirs[@]}"); fi

	redir "$@"

}

function filter_fd() # usage: (fd=# [redirs=] filter_fd filter_cmd...; \

# with filter...) # be sure ${redirs[@]} is not set to an outer value

# useful e.g. to filter logging output or highlight errors

{

	echo_func; kw_params fd; : "${fd?}"

	set_fds "$fd>" >(pipe_delay; stdout2fd "$@")

	pipe_delay; pipe_delay # wait for >()'s pipe_delay and initial logging

}

alias filter_fd='"filter_fd" ' # last space alias-expands next word

stderr2stdout() # usage: { stderr2stdout cmd...|use stderr...; } 41>&1

# **IMPORTANT**: fd 41 must later be redirected back to fd 1

# unlike `2>&1`, logs stderr

# redirects the command stdout to fd 41 to avoid collision with stderr

{

	echo_func

	# command causes log_fd to be re-filtered, so that stderr is also filtered.

	# fd 2 is *not* redirected back to fd 2, to allow log-filtering out an

	# otherwise-confusing benign error.

	"$@" 2> >(command tee /dev/fd/"$log_fd") >&41 # redirects 2->{1,log_fd}

}

stdout_contains()

# usage: { stderr2stdout cmd|stdout_contains echo_run grep ...; } 41>&1

{ echo_func; pipe_delay; pipe_delay; pipe_delay; "$@"|echo_stdout >/dev/null; }

stderr_matches() # usage: pattern=... [ignore_e=#] stderr_matches cmd...

{

	echo_func; kw_params pattern ignore_e; : "${pattern?}"

	if test "$ignore_e"; then local benign_error=1; fi

	# not necessary to allow callers to handle the error themselves (which would

	# require *every* caller to wrap this function in prep_try/rethrow), because

	# they would just handle it by errexiting anyways

	prep_try

	set +o errexit # avoid errexiting since @PIPESTATUS will be used instead

	{ stderr2stdout "$@"|stdout_contains echo_run grep -E "$pattern"; } 41>&1

	local PIPESTATUS_=("${PIPESTATUS[@]}") # save b/c it's reset after each cmd

	set -o errexit

	# handle any error

	e="${PIPESTATUS_[0]}" # 1st command's exit status -> $e

	ignore_e "$ignore_e" # also works w/ ignore_e=''

	rethrow_exit

	return "${PIPESTATUS_[1]}" # 2nd command's exit status -> $?

}

fi # load new aliases

if self_being_included; then

function ignore_err_msg() # usage: pattern=... ignore_err_msg cmd...

# unlike `|| true`, this suppresses only errors caused by a particular error

# *message*, rather than all error exit statuses

{

	echo_func; kw_params pattern; : "${pattern?}"

	stderr_matches "$@" || true # also ignore false exit status on no match

}

alias ignore_err_msg='"ignore_err_msg" ' # last space alias-expands next word

# convention: use fd 40/41/42 for command-specific alternate stdin/stdout/stderr

# mnemonic: 4 looks like A for Alternate

# do NOT use 1x, which are used by eval (which is used by set_fds())

# do NOT use 2x, which we use as global stdin/stdout/stderr

# do NOT use 3x, which we use for logging

setup_log_fd() # view logging output at verbosity >= 5

{

	log_local; log+ 4; log-- echo_func 

	fd_set_default '30>&2' || true # stdlog

	log_fd=30 # stdlog

}

setup_log_fd

set_global_fds()

# allows commands to access global stdin/stdout/stderr using fd 20/21/22

# this works even when /dev/tty isn't available

# view logging output at verbosity >= 3

{

	log_local; log+ 2; log-- echo_func

	# ignore errors if a source fd isn't open

	fd_set_default '20<&0' || true

	fd_set_default '21>&1' || true

	fd_set_default '22>&2' || true

}

set_global_fds

# usage: explicit_errors_only=1 script...

# show only explicitly-displayed errors (which have been redirected to fd 22)

# most of the time this has the same effect as `verbosity=0 script...`,

# which displays everything that isn't explicitly hidden

# this option should only be used for testing the explicit error displaying

if test "$explicit_errors_only"; then disable_logging; fi

echo_vars is_outermost

#### paths

top_script="${BASH_SOURCE[${#BASH_SOURCE[@]}-1]}"

	# outermost script; unlike $0, also defined for .-scripts

top_symlink_dir="$(dirname "$top_script")"; echo_vars top_symlink_dir

top_symlink_dir_abs="$(realpath "$top_symlink_dir")"

	echo_vars top_symlink_dir_abs

top_script_abs="$(realpath "$top_script")"; echo_vars top_script_abs

	# realpath this before doing any cd so this points to the right place

top_dir_abs="$(dirname "$top_script_abs")"; echo_vars top_dir_abs

set_paths()

{

	top_script="$(log++ canon_rel_path "$top_script_abs")" || return

		echo_vars top_script

	top_dir="$(dirname "$top_script")" || return; echo_vars top_dir

}

set_paths

# usage: $(enter_top_dir; cmd...)

function enter_top_dir() { echo_func; cd "$top_dir"; }

alias enter_top_dir='log++; "enter_top_dir"'

# usage: in_top_dir cmd...

function in_top_dir() { echo_func; (enter_top_dir; "$@"); }

alias in_top_dir='"in_top_dir" ' # last space alias-expands next word