xbmk: don't use backticks for command substitution

the newer way handles escaped characters better, and it
can be nested more easily. it's also more readable.

personally, i prefer the old way, because it's more
minimalist, but it occurs to me that a lot of people
nowadays don't know about backticks, but they do know
of the modern way.

to make the code more readable, i have modernised it.

Signed-off-by: Leah Rowe <leah@libreboot.org>

10 files changed, 58 insertions, 56 deletions

diff --git a/config/data/coreboot/mkhelper.cfg b/config/data/coreboot/mkhelper.cfg
index d4de718e..19626289 100644
--- a/config/data/coreboot/mkhelper.cfg
+++ b/config/data/coreboot/mkhelper.cfg
@@ -8,8 +8,8 @@ seavgabiosrom="elf/seabios/default/default/libgfxinit/vgabios.bin"
 pv="payload_seabios payload_memtest payload_grub payload_grubsea"
 v="initmode ubootelf grub_scan_disk uboot_config grubtree grubelf pname"
 v="$v displaymode tmprom newrom payload_uboot"
-eval `setvars "n" $pv`
-eval `setvars "" $v`
+eval "$(setvars "n" $pv)"
+eval "$(setvars "" $v)"
 
 premake="corebootpremake"
 mkhelper="coreboot_pad_one_byte"
diff --git a/include/get.sh b/include/get.sh
index ecfd0ba5..bee00fe1 100644
--- a/include/get.sh
+++ b/include/get.sh
@@ -2,8 +2,8 @@
 # Copyright (c) 2020-2021,2023-2025 Leah Rowe <leah@libreboot.org>
 # Copyright (c) 2022 Caleb La Grange <thonkpeasant@protonmail.com>
 
-eval "`setvars "" loc url bkup_url subcurl subhash subgit subgit_bkup \
-    depend subcurl_bkup`"
+eval "$(setvars "" loc url bkup_url subcurl subhash subgit subgit_bkup \
+    depend subcurl_bkup)"
 
 tmpgit="$xbtmp/gitclone"
 tmpgitcache="$xbtmp/tmpgit"
@@ -16,8 +16,8 @@ fetch_targets()
 
 fetch_project()
 {
-	eval "`setvars "" xtree`"
-	eval "`setcfg "config/git/$project/pkg.cfg"`"
+	eval "$(setvars "" xtree)"
+	eval "$(setcfg "config/git/$project/pkg.cfg")"
 
 	chkvars url bkup_url && [ -n "$xtree" ] && x_ ./mk -f coreboot "$xtree"
 	[ -z "$depend" ] || for d in $depend ; do
@@ -55,8 +55,8 @@ git_prep()
 fetch_submodule()
 {
 	mcfgdir="$mdir/${1##*/}"; eval \
-	    "`setvars "" subhash subgit subgit_bkup subcurl subcurl_bkup st`"
-	eval "`setcfg "$mcfgdir/module.cfg" 0`"
+	    "$(setvars "" subhash subgit subgit_bkup subcurl subcurl_bkup st)"
+	eval "$(setcfg "$mcfgdir/module.cfg" 0)"
 
 	for xt in git curl; do
 		_seval="if [ -n \"\$sub$xt\" ] || [ -n \"\$sub${xt}_bkup\" ]"
@@ -133,7 +133,7 @@ try_copy()
 
 try_git()
 {
-	gitdest="`findpath "$1"`" || err "Can't get readpath for '$1'"
+	gitdest="$(findpath "$1" || err "Can't get readpath for '$1'")" || err
 	x_ rm -Rf "$tmpgitcache"
 
 	[ -d "$gitdest" ] || ( x_ git clone "$2" "$tmpgitcache" ) || return 1
diff --git a/include/init.sh b/include/init.sh
index d2ec4f16..4b389b69 100644
--- a/include/init.sh
+++ b/include/init.sh
@@ -13,13 +13,13 @@ projectsite="https://libreboot.org/"
 [ -z "${PATH+x}" ] && \
     export PATH="/usr/local/bin:/usr/bin:/bin:/usr/local/games:/usr/games"
 
-eval "`setvars "" _nogit board reinstall versiondate aur_notice configdir \
+eval "$(setvars "" _nogit board reinstall versiondate aur_notice configdir \
     datadir version xbmkpwd relname xbmkpwd xbtmp python pyver xbmklock \
-    cvxbmk cvchk xbmkpath is_child basetmp`"
+    cvxbmk cvchk xbmkpath is_child basetmp)"
 
 xbmk_init()
 {
-	xbmkpwd="`pwd`" || err "Cannot generate PWD"
+	xbmkpwd="$(pwd || err "Cannot generate PWD")" || err
 	xbmklock="$xbmkpwd/lock"
 	basetmp="$xbmkpwd/xbmkwd"
 
@@ -41,7 +41,7 @@ xbmkpkg()
 	[ $# -lt 2 ] && err "fewer than two arguments"
 	[ $# -gt 2 ] && reinstall="$3"
 
-	eval "`setcfg "config/dependencies/$2"`"
+	eval "$(setcfg "config/dependencies/$2")"
 
 	chkvars pkg_add pkglist
 	x_ $pkg_add $pkglist
@@ -94,12 +94,12 @@ xbmk_set_env()
 
 xbmk_child_set_tmp()
 {
-	eval `setvars "" xbtmp badtmp xbtmpchk xbtmpname`
+	eval "$(setvars "" xbtmp badtmp xbtmpchk xbtmpname)"
 
 	[ -z "${TMPDIR+x}" ] && export TMPDIR="$basetmp"
 
 	# extremely pedantic safety checks on TMPDIR
-	xbtmpchk="`findpath "$TMPDIR" || err`" || err
+	xbtmpchk="$(findpath "$TMPDIR" || err "!findpath $TMPDIR")" || err
 	[ "$xbtmpchk" = "${xbtmpchk#"$basetmp/"}" ] && \
 	    badtmp="not a subdirectory in $basetmp"
 	[ -z "$badtmp" ] && xbtmpname="${xbtmpchk#"$basetmp/"}" && \
@@ -130,7 +130,7 @@ xbmk_parent_check_tmp()
 {
 	export TMPDIR="$basetmp"
 
-	xbmklist="`mktemp || err "can't make tmplist"`" || err
+	xbmklist="$(mktemp || err "can't make tmplist")" || err
 	x_ rm -f "$xbmklist"
 	x_ touch "$xbmklist"
 	for xtmpdir in "$basetmp"/xbmk_*; do
@@ -140,7 +140,7 @@ xbmk_parent_check_tmp()
 	done
 
 	# set up a unified temporary directory, for common deletion later:
-	export TMPDIR="`mktemp -d -t xbmk_XXXXXXXX || err`" || err
+	export TMPDIR="$(x_ mktemp -d -t xbmk_XXXXXXXX)" || err
 	xbtmp="$TMPDIR"
 
 	while read -r xtmpdir; do
@@ -198,7 +198,7 @@ xbmk_set_pyver()
 	pybin python3 1>/dev/null || python="python"
 	pyver="2" && [ "$python" = "python3" ] && pyver="3"
 	pybin "$python" 1>/dev/null || pyver=""
-	[ -z "$pyver" ] || "`pybin "$python"`" -c "$pyv" 1>/dev/null \
+	[ -z "$pyver" ] || "$(x_ pybin "$python")" -c "$pyv" 1>/dev/null \
 	    2>/dev/null || err "Cannot detect host Python version."
 	[ -n "$pyver" ] && \
 	    pyver="$("$(pybin "$python")" -c "$pyv" | awk '{print $1}')" && \
@@ -209,7 +209,7 @@ xbmk_set_pyver()
 	# set up python v3.x in PATH, in case it's not set up correctly.
 	# see code above that detected the correct python3 command.
 	x_ cd "$xbtmp/xbmkpath"
-	x_ ln -s "`pybin "$python"`" python
+	x_ ln -s "$(x_ pybin "$python")" python || err
 	) || err "Can't set up python symlink in $xbtmp/xbmkpath"; :
 }
 
@@ -226,7 +226,7 @@ pybin()
 
 	# ideally, don't rely on PATH or hardcoded paths if python venv.
 	# use the *real*, direct executable linked to by the venv symlink
-	if [ $venv -gt 0 ] && [ -L "`command -v "$1" 2>/dev/null`" ]; then
+	if [ $venv -gt 0 ] && [ -L "$(command -v "$1" 2>/dev/null)" ]; then
 		pypath="$(findpath \
 		    "$(command -v "$1" 2>/dev/null)" 2>/dev/null || :)"
 		[ -e "$pypath" ] && [ ! -d "$pypath" ] && \
@@ -257,7 +257,8 @@ xbmk_git_init()
 	x_ date --version | grep "GNU coreutils" 1>/dev/null 2>/dev/null || \
 	    err "Non-GNU date implementation; current use relies on GNU date"
 
-	eval "`setvars "$(date -Rud @$versiondate)" cdate _nogit`"
+	eval "$(setvars "$(x_ date -Rud @$versiondate)" cdate _nogit || err)" \
+	    err
 
 	x_ git init 1>/dev/null 2>/dev/null
 	x_ git add -A . 1>/dev/null 2>/dev/null
diff --git a/include/inject.sh b/include/inject.sh
index 77d99874..4ed6d7b6 100644
--- a/include/inject.sh
+++ b/include/inject.sh
@@ -12,15 +12,15 @@ cv="CONFIG_GBE_BIN_PATH"
 [ -n "$cvxbmk" ] && cv="$cv $cvxbmk"
 [ -n "$cvchk" ] && cv="$cv $cvchk"
 
-eval "`setvars "" archive boarddir IFD_platform ifdprefix tree new_mac \
-    tmpromdir board xchanged $cv`"
+eval "$(setvars "" archive boarddir IFD_platform ifdprefix tree new_mac \
+    tmpromdir board xchanged $cv)"
 
 inject()
 {
 	remkdir "$tmpromdel"
 
 	[ $# -lt 1 ] && err "No options specified"
-	eval "`setvars "" nuke new_mac xchanged`"
+	eval "$(setvars "" nuke new_mac xchanged)"
 
 	archive="$1";
 	new_mac="xx:xx:xx:xx:xx:xx"
@@ -53,7 +53,8 @@ check_release()
 	[ -L "$archive" ] && err "'$archive' is a symlink"
 	e "$archive" f missing && err "'$archive' missing"
 
-	archivename="`basename "$archive"`" || err "Can't get '$archive' name"
+	archivename="$(basename "$archive" || err "Can't get '$archive' name")" \
+	    || err
 	[ -z "$archivename" ] && err "Can't determine archive name"
 
 	case "$archivename" in
@@ -73,7 +74,7 @@ check_target()
 	[ "$board" = "${board#serprog_}" ] || return 1
 	boarddir="$cbcfgsdir/$board"
 
-	eval "`setcfg "$boarddir/target.cfg"`"
+	eval "$(setcfg "$boarddir/target.cfg")"
 	chkvars tree && x_ ./mk -d coreboot "$tree"
 
 	ifdtool="elf/coreboot/$tree/ifdtool"
@@ -104,7 +105,7 @@ readkconfig()
 {
 	x_ rm -f "$xbtmp/cbcfg"
 	fx_ scankconfig x_ find "$boarddir/config" -type f
-	eval "`setcfg "$xbtmp/cbcfg" 1`"
+	eval "$(setcfg "$xbtmp/cbcfg" 1)"
 	setvfile "$@" || return 1; :
 }
 
diff --git a/include/lib.sh b/include/lib.sh
index a2b93a97..1f8687fb 100644
--- a/include/lib.sh
+++ b/include/lib.sh
@@ -32,11 +32,11 @@ xbmk_sanitize_version()
 {
 	[ -n "$version" ] || return 0; :
 
-	version="`printf "%s\n" "$version" | sed -e 's/\t//g'`"
-	version="`printf "%s\n" "$version" | sed -e 's/\ //g'`"
-	version="`printf "%s\n" "$version" | sed -e 's/\.\.//g'`"
-	version="`printf "%s\n" "$version" | sed -e 's/\.\///g'`"
-	version="`printf "%s\n" "$version" | sed -e 's/\//-/g'`"
+	version="$(printf "%s\n" "$version" | sed -e 's/\t//g')"
+	version="$(printf "%s\n" "$version" | sed -e 's/\ //g')"
+	version="$(printf "%s\n" "$version" | sed -e 's/\.\.//g')"
+	version="$(printf "%s\n" "$version" | sed -e 's/\.\///g')"
+	version="$(printf "%s\n" "$version" | sed -e 's/\//-/g')"
 	version="${version#-}"
 
 	[ -n "$version" ] || err "'version' empty after sanitization"; :
@@ -103,8 +103,8 @@ findpath()
 {
 	[ $# -gt 0 ] || err "findpath: No arguments provided"
 	while [ $# -gt 0 ]; do
-		found="`readlink -f "$1" 2>/dev/null`" || return 1; :
-		[ -n "$found" ] || found="`realpath "$1" 2>/dev/null`" || \
+		found="$(readlink -f "$1" 2>/dev/null)" || return 1; :
+		[ -n "$found" ] || found="$(realpath "$1" 2>/dev/null)" || \
 		    return 1; :
 		printf "%s\n" "$found"
 		shift 1
@@ -113,7 +113,7 @@ findpath()
 
 pad_one_byte()
 {
-	paddedfile="`mktemp`" || err "mktemp pad_one_byte"
+	paddedfile="$(mktemp || err "mktemp pad_one_byte")" || err
 	x_ cat "$1" config/data/coreboot/0 > "$paddedfile" || err "!pad $1"; :
 	x_ mv "$paddedfile" "$1"
 }
@@ -123,14 +123,14 @@ unpad_one_byte()
 	xromsize="$(expr $(stat -c '%s' "$1") - 1)" || err "!int"
 	[ $xromsize -lt 524288 ] && err "too small, $xromsize: $1"
 
-	unpaddedfile="`mktemp`" || err "mktemp unpad_one_byte"
+	unpaddedfile="$(mktemp || err "mktemp unpad_one_byte")" || err
 	x_ dd if="$1" of="$unpaddedfile" bs=$xromsize count=1
 	x_ mv "$unpaddedfile" "$1"
 }
 
 fx_()
 {
-	fd="`mktemp || err "can't create tmpfile"`" || err
+	fd="$(mktemp || err "can't create tmpfile")" || err
 	x_ rm -f "$fd" && x_ touch "$fd"
 	xx="$1" && shift 1
 	"$@" 2>/dev/null | sort 1>"$fd" 2>/dev/null || err "FATAL: !sort fx_"
diff --git a/include/mrc.sh b/include/mrc.sh
index 775831f8..5cbf7148 100644
--- a/include/mrc.sh
+++ b/include/mrc.sh
@@ -4,7 +4,7 @@
 # Modifications in this version are Copyright 2021,2023-2025 Leah Rowe.
 # Original copyright detailed in repo: https://review.coreboot.org/coreboot/
 
-eval "`setvars "" MRC_url MRC_url_bkup MRC_hash MRC_board SHELLBALL`"
+eval "$(setvars "" MRC_url MRC_url_bkup MRC_hash MRC_board SHELLBALL)"
 
 extract_refcode()
 {
diff --git a/include/release.sh b/include/release.sh
index 2c94b00c..906cd7e0 100644
--- a/include/release.sh
+++ b/include/release.sh
@@ -1,7 +1,7 @@
 # SPDX-License-Identifier: GPL-3.0-or-later
 # Copyright (c) 2023-2025 Leah Rowe <leah@libreboot.org>
 
-eval "`setvars "" reldir reldest vdir rsrc relmode`"
+eval "$(setvars "" reldir reldest vdir rsrc relmode)"
 
 release()
 {
@@ -21,7 +21,7 @@ release()
 	[ -e "$reldest" ] && \
 	    err "already exists: \"$reldest\""
 
-	vdir="`mktemp -d || err "can't make vdir"`" || err
+	vdir="$(mktemp -d || err "can't make vdir")" || err
 	vdir="$vdir/$version"
 
 	rsrc="$vdir/${relname}_src"
diff --git a/include/rom.sh b/include/rom.sh
index bd58f974..223a84f3 100644
--- a/include/rom.sh
+++ b/include/rom.sh
@@ -32,8 +32,8 @@ copyps1bios()
 
 mkpayload_grub()
 {
-	eval "`setvars "" grub_modules grub_install_modules`"
-	$dry eval "`setcfg "$grubdata/module/$tree"`"
+	eval "$(setvars "" grub_modules grub_install_modules)"
+	$dry eval "$(setcfg "$grubdata/module/$tree")"
 	$dry x_ rm -f "$srcdir/grub.elf"; $dry \
 	x_ "$srcdir/grub-mkstandalone" --grub-mkimage="$srcdir/grub-mkimage" \
 	    -O i386-coreboot -o "$srcdir/grub.elf" -d "${srcdir}/grub-core/" \
@@ -256,7 +256,7 @@ cprom()
 	    newrom="${newrom%.rom}_${tmpnew%.gkb}.rom"
 
 	irom="$tmprom"
-	[ $# -lt 1 ] || irom="`mktemp || err "!mk irom, $(echo "$@")"`" || err
+	[ $# -lt 1 ] || irom="$(mktemp || err "!mk irom, $(echo "$@")")" || err
 	[ $# -gt 0 ] && x_ cp "$tmprom" "$irom" && cpcmd="mv"
 
 	[ $# -gt 0 ] && [ "${1%.gkb}" != "$1" ] && \
diff --git a/include/tree.sh b/include/tree.sh
index e5030064..9d9cc181 100644
--- a/include/tree.sh
+++ b/include/tree.sh
@@ -3,11 +3,11 @@
 # Copyright (c) 2022 Ferass El Hafidi <vitali64pmemail@protonmail.com>
 # Copyright (c) 2023-2025 Leah Rowe <leah@libreboot.org>
 
-eval "`setvars "" xarch srcdir premake gnatdir xlang mode makeargs elfdir cmd \
+eval "$(setvars "" xarch srcdir premake gnatdir tree mode makeargs elfdir cmd \
     project target target_dir targets xtree _f release bootstrapargs mkhelper \
     autoconfargs listfile autogenargs btype rev build_depend gccdir cmakedir \
     defconfig postmake mkhelpercfg dry dest_dir mdir cleanargs gccver gccfull \
-    gnatver gnatfull do_make badhash badtghash tree`"
+    gnatver gnatfull do_make badhash badtghash xlang)"
 
 trees()
 {
@@ -128,16 +128,16 @@ handle_defconfig()
 
 configure_project()
 {
-	eval "`setvars "" cleanargs build_depend autoconfargs xtree postmake \
+	eval "$(setvars "" cleanargs build_depend autoconfargs xtree postmake \
 	    makeargs btype mkhelper bootstrapargs premake release xlang xarch \
-	    badhash badtghash`"
+	    badhash badtghash)"
 	_tcfg="$1/target.cfg"
 	[ -f "$_tcfg" ] || btype="auto"
-	e "$datadir/mkhelper.cfg" f && eval "`setcfg "$datadir/mkhelper.cfg"`"
+	e "$datadir/mkhelper.cfg" f && eval "$(setcfg "$datadir/mkhelper.cfg")"
 
 	while e "$_tcfg" f || [ "$cmd" != "build_project" ]; do
-		eval "`setvars "" rev tree`"
-		eval "`setcfg "$_tcfg"`"
+		eval "$(setvars "" rev tree)"
+		eval "$(setcfg "$_tcfg")"
 		printf "Loading %s config: %s\n" "$project" "$_tcfg"
 
 		[ "$_f" = "-d" ] && build_depend="" # dry run
@@ -191,7 +191,7 @@ delete_old_project_files()
 
 project_up_to_date()
 {
-	eval "`setvars "" old_hash hash`"
+	eval "$(setvars "" old_hash hash)"
 	hashdir="$1"
 	hashname="$2"
 	badhashvar="$3"
@@ -252,7 +252,7 @@ check_gnu_path()
 {
 	command -v "$1" 1>/dev/null || err "Host '$1' unavailable"
 
-	eval "`setvars "" gccver gccfull gnatver gnatfull gccdir gnatdir`"
+	eval "$(setvars "" gccver gccfull gnatver gnatfull gccdir gnatdir)"
 	x_ gnu_setver "$1" "$1" || err "Command '$1' unavailable."
 	gnu_setver "$2" "$2" || :
 
@@ -281,7 +281,7 @@ check_gnu_path()
 gnu_setver()
 {
 	eval "$2 --version 1>/dev/null 2>/dev/null || return 1"
-	eval "$1ver=\"`"$2" --version 2>/dev/null | head -n1`\""
+	eval "$1ver=\"$("$2" --version 2>/dev/null | head -n1)\""
 	eval "$1ver=\"\${$1ver##* }\""
 	eval "$1full=\"\$$1ver\""
 	eval "$1ver=\"\${$1ver%%.*}\""; :
diff --git a/include/vendor.sh b/include/vendor.sh
index 6e379236..b4e89616 100644
--- a/include/vendor.sh
+++ b/include/vendor.sh
@@ -33,7 +33,7 @@ cvxbmk="CONFIG_ME_BIN_PATH CONFIG_SMSC_SCH5545_EC_FW_FILE CONFIG_FSP_FULL_FD \
     CONFIG_IFD_BIN_PATH CONFIG_MRC_FILE CONFIG_FSP_M_CBFS"
 
 # lbmk-specific extensions; mostly used for downloading vendor files
-eval "`setvars "" has_hashes EC_hash DL_hash DL_url_bkup MRC_refcode_gbe vcfg \
+eval "$(setvars "" has_hashes EC_hash DL_hash _pre_dest MRC_refcode_gbe vcfg \
     E6400_VGA_DL_hash E6400_VGA_DL_url E6400_VGA_DL_url_bkup E6400_VGA_offset \
     E6400_VGA_romname SCH5545EC_DL_url_bkup SCH5545EC_DL_hash _dest mecleaner \
     kbc1126_ec_dump MRC_refcode_cbtree _dl SCH5545EC_DL_url EC_url rom DL_url \
@@ -41,7 +41,7 @@ eval "`setvars "" has_hashes EC_hash DL_hash DL_url_bkup MRC_refcode_gbe vcfg \
     ME11version ME11sku ME11pch _me _metmp mfs TBFW_url_bkup TBFW_url cbdir \
     TBFW_hash TBFW_size hashfile EC_url_bkup FSPM_bin_hash FSPS_bin_hash \
     EC_FW1_hash EC_FW2_hash ME_bin_hash MRC_bin_hash REF_bin_hash _dl_bin \
-    SCH5545EC_bin_hash TBFW_bin_hash E6400_VGA_bin_hash _pre_dest`"
+    SCH5545EC_bin_hash TBFW_bin_hash E6400_VGA_bin_hash DL_url_bkup)"
 
 download()
 {
@@ -272,7 +272,7 @@ setvfile()
 
 getvfile()
 {
-	eval "`setcfg "config/vendor/$vcfg/pkg.cfg" 1`"
+	eval "$(setcfg "config/vendor/$vcfg/pkg.cfg" 1)"
 	bootstrap && [ $# -gt 0 ] && getfiles && return 0 # download
 	fx_ prep x_ find "$tmpromdir" -maxdepth 1 -type f -name "*.rom"
 	( check_vendor_hashes ) || err "$archive: Can't verify hashes"; :