tests: convert nearly all `...` expressions to $(...)

Exempt init.sh because it runs before we're assured to have a
shell that groks $(...).  Exempt *.mk because "$" would have to
be doubled, and besides, any `...` expression in a .mk file is
almost certainly evaluated before init.sh is run.  Finally, also
exempt the perl-based tests, because perl's `...` cannot be
converted to $(...).  Do that by running this command:

git grep -l '`.*`' tests \
  | grep -Ev 'init\.sh|\.mk$' | xargs grep -Lw perl \
  | xargs perl -pi -e 's/`(.*?)`/\$($1)/g'

One minor fix-up change was required after that, due to how
quoting differs:
diff --git a/tests/chmod/equals b/tests/chmod/equals
-    expected_perms=$(eval 'echo \$expected_'$dest)
+    expected_perms=$(eval 'echo $expected_'$dest)

Another was to make these required quoting adjustments:
diff --git a/tests/misc/stty b/tests/misc/stty
...
-  rev=$(eval echo "\\\$REV_$opt")
+  rev=$(eval echo "\$REV_$opt")
...
-      rev1=$(eval echo "\\\$REV_$opt1")
-      rev2=$(eval echo "\\\$REV_$opt2")
+      rev1=$(eval echo "\$REV_$opt1")
+      rev2=$(eval echo "\$REV_$opt2")

Also, transform two files that were needlessly excluded above:
(both use perl, but are mostly bourne shell)

  perl -pi -e 's/`(.*?)`/\$($1)/g' \
    tests/du/long-from-unreadable tests/init.cfg

22 files changed, 50 insertions, 50 deletions

diff --git a/tests/cp/acl b/tests/cp/acl
index 94b7af69b..26a7f420a 100755
--- a/tests/cp/acl
+++ b/tests/cp/acl
@@ -31,22 +31,22 @@ touch a/file || framework_failure_
 
 # Ensure that setfacl and getfacl work on this file system.
 skip=no
-acl1=`cd a && getfacl file` || skip=yes
+acl1=$(cd a && getfacl file) || skip=yes
 setfacl -m user:bin:rw- a/file 2> /dev/null || skip=yes
 test $skip = yes &&
   skip_ "'.' is not on a suitable file system for this test"
 
 # copy a file without preserving permissions
 cp a/file b/ || fail=1
-acl2=`cd b && getfacl file` || framework_failure_
+acl2=$(cd b && getfacl file) || framework_failure_
 test "$acl1" = "$acl2" || fail=1
 
 # Update with acl set above
-acl1=`cd a && getfacl file` || framework_failure_
+acl1=$(cd a && getfacl file) || framework_failure_
 
 # copy a file, preserving permissions
 cp -p a/file b/ || fail=1
-acl2=`cd b && getfacl file` || framework_failure_
+acl2=$(cd b && getfacl file) || framework_failure_
 test "$acl1" = "$acl2" || fail=1
 
 # copy a file, preserving permissions, with --attributes-only
@@ -54,7 +54,7 @@ echo > a/file || framework_failure_ # add some data
 test -s a/file || framework_failure_
 cp -p --attributes-only a/file b/ || fail=1
 test -s b/file && fail=1
-acl2=`cd b && getfacl file` || framework_failure_
+acl2=$(cd b && getfacl file) || framework_failure_
 test "$acl1" = "$acl2" || fail=1
 
 Exit $fail
diff --git a/tests/cp/cp-a-selinux b/tests/cp/cp-a-selinux
index 11758170d..b85298488 100755
--- a/tests/cp/cp-a-selinux
+++ b/tests/cp/cp-a-selinux
@@ -24,7 +24,7 @@ print_ver_ cp
 require_root_
 require_selinux_
 
-cwd=`pwd`
+cwd=$(pwd)
 cleanup_() { cd /; umount "$cwd/mnt"; }
 
 # This context is special: it works even when mcstransd isn't running.
diff --git a/tests/cp/cp-mv-backup b/tests/cp/cp-mv-backup
index 3e6b6ff90..030f722dc 100755
--- a/tests/cp/cp-mv-backup
+++ b/tests/cp/cp-mv-backup
@@ -35,7 +35,7 @@ for prog in cp mv; do
     for opt in none off  numbered t  existing nil  simple never; do
       touch $initial_files
         $prog --backup=$opt x y || fail=1
-      echo $initial_files $opt: `ls [xy]*`; rm -f x y y~ y.~?~
+      echo $initial_files $opt: $(ls [xy]*); rm -f x y y~ y.~?~
     done
   done
 done
diff --git a/tests/cp/cp-mv-enotsup-xattr b/tests/cp/cp-mv-enotsup-xattr
index 76ede2e3e..66e54cf11 100755
--- a/tests/cp/cp-mv-enotsup-xattr
+++ b/tests/cp/cp-mv-enotsup-xattr
@@ -23,7 +23,7 @@ print_ver_ cp mv
 
 require_root_
 
-cwd=`pwd`
+cwd=$(pwd)
 cleanup_() { cd /; umount "$cwd/noxattr"; umount "$cwd/xattr"; }
 
 skip=0
diff --git a/tests/cp/cp-parents b/tests/cp/cp-parents
index 85fccd63b..b325c722b 100755
--- a/tests/cp/cp-parents
+++ b/tests/cp/cp-parents
@@ -49,10 +49,10 @@ test -d d/f && fail=1
 chmod go=w d/a || framework_failure_
 cp -a --parents d/a/b/c e || fail=1
 cp -a --parents sym/b/c g || fail=1
-p=`ls -ld e/d|cut -b-10`; case $p in drwxr-xr-x);; *) fail=1;; esac
-p=`ls -ld e/d/a|cut -b-10`; case $p in drwx-w--w-);; *) fail=1;; esac
-p=`ls -ld g/sym|cut -b-10`; case $p in drwx-w--w-);; *) fail=1;; esac
-p=`ls -ld e/d/a/b/c|cut -b-10`; case $p in drwxr-xr-x);; *) fail=1;; esac
-p=`ls -ld g/sym/b/c|cut -b-10`; case $p in drwxr-xr-x);; *) fail=1;; esac
+p=$(ls -ld e/d|cut -b-10); case $p in drwxr-xr-x);; *) fail=1;; esac
+p=$(ls -ld e/d/a|cut -b-10); case $p in drwx-w--w-);; *) fail=1;; esac
+p=$(ls -ld g/sym|cut -b-10); case $p in drwx-w--w-);; *) fail=1;; esac
+p=$(ls -ld e/d/a/b/c|cut -b-10); case $p in drwxr-xr-x);; *) fail=1;; esac
+p=$(ls -ld g/sym/b/c|cut -b-10); case $p in drwxr-xr-x);; *) fail=1;; esac
 
 Exit $fail
diff --git a/tests/cp/fail-perm b/tests/cp/fail-perm
index 3835f6b0f..2c37d6fb1 100755
--- a/tests/cp/fail-perm
+++ b/tests/cp/fail-perm
@@ -31,7 +31,7 @@ cp -pR D DD > /dev/null 2>&1 && fail=1
 
 # Permissions on DD must be 'dr-x------'
 
-mode=`ls -ld DD|cut -b-10`
+mode=$(ls -ld DD|cut -b-10)
 test "$mode" = dr-x------ || fail=1
 
 chmod 0 D
diff --git a/tests/cp/fiemap-empty b/tests/cp/fiemap-empty
index efa4b660d..4ba4ee30e 100755
--- a/tests/cp/fiemap-empty
+++ b/tests/cp/fiemap-empty
@@ -29,7 +29,7 @@ fiemap_capable_ fiemap_chk ||
   skip_ 'this file system lacks FIEMAP support'
 rm fiemap_chk
 
-# TODO: rather than requiring `fallocate`, possible add
+# TODO: rather than requiring $(fallocate), possible add
 # this functionality to truncate --alloc
 fallocate --help >/dev/null || skip_ 'The fallocate utility is required'
 fallocate -l 1 -n falloc.test ||
diff --git a/tests/cp/file-perm-race b/tests/cp/file-perm-race
index 46db6f974..fbc9a86eb 100755
--- a/tests/cp/file-perm-race
+++ b/tests/cp/file-perm-race
@@ -46,7 +46,7 @@ cp_pid=$!
   echo foo
 ) >fifo
 
-case `cat ls.out` in
+case $(cat ls.out) in
 -???------*) ;;
 *) fail=1;;
 esac
diff --git a/tests/cp/link-preserve b/tests/cp/link-preserve
index 785c9e40a..9ca1705f5 100755
--- a/tests/cp/link-preserve
+++ b/tests/cp/link-preserve
@@ -28,8 +28,8 @@ test -f c/a || framework_failure_
 test -f c/b || framework_failure_
 
 
-a_inode=`ls -i c/a|sed 's,c/.*,,'`
-b_inode=`ls -i c/b|sed 's,c/.*,,'`
+a_inode=$(ls -i c/a|sed 's,c/.*,,')
+b_inode=$(ls -i c/b|sed 's,c/.*,,')
 test "$a_inode" = "$b_inode" || fail=1
 # --------------------------------------
 
@@ -38,8 +38,8 @@ touch a
 ln -s a b
 mkdir c
 cp --preserve=links -R -H a b c
-a_inode=`ls -i c/a|sed 's,c/.*,,'`
-b_inode=`ls -i c/b|sed 's,c/.*,,'`
+a_inode=$(ls -i c/a|sed 's,c/.*,,')
+b_inode=$(ls -i c/b|sed 's,c/.*,,')
 test "$a_inode" = "$b_inode" || fail=1
 # --------------------------------------
 
@@ -47,24 +47,24 @@ test "$a_inode" = "$b_inode" || fail=1
 # and translates to hard-linked a and b in the destination dir.
 rm -rf a b c d; mkdir d; (cd d; touch a; ln -s a b)
 cp --preserve=links -R -L d c
-a_inode=`ls -i c/a|sed 's,c/.*,,'`
-b_inode=`ls -i c/b|sed 's,c/.*,,'`
+a_inode=$(ls -i c/a|sed 's,c/.*,,')
+b_inode=$(ls -i c/b|sed 's,c/.*,,')
 test "$a_inode" = "$b_inode" || fail=1
 # --------------------------------------
 
 # Same as above, but starting with a/b hard linked.
 rm -rf a b c d; mkdir d; (cd d; touch a; ln a b)
 cp --preserve=links -R -L d c
-a_inode=`ls -i c/a|sed 's,c/.*,,'`
-b_inode=`ls -i c/b|sed 's,c/.*,,'`
+a_inode=$(ls -i c/a|sed 's,c/.*,,')
+b_inode=$(ls -i c/b|sed 's,c/.*,,')
 test "$a_inode" = "$b_inode" || fail=1
 # --------------------------------------
 
 # Ensure that --no-preserve=links works.
 rm -rf a b c d; mkdir d; (cd d; touch a; ln a b)
 cp -dR --no-preserve=links d c
-a_inode=`ls -i c/a|sed 's,c/.*,,'`
-b_inode=`ls -i c/b|sed 's,c/.*,,'`
+a_inode=$(ls -i c/a|sed 's,c/.*,,')
+b_inode=$(ls -i c/b|sed 's,c/.*,,')
 test "$a_inode" = "$b_inode" && fail=1
 # --------------------------------------
 
@@ -73,8 +73,8 @@ rm -rf a b c d
 touch a; ln a b
 mkdir c
 cp -d a b c
-a_inode=`ls -i c/a|sed 's,c/.*,,'`
-b_inode=`ls -i c/b|sed 's,c/.*,,'`
+a_inode=$(ls -i c/a|sed 's,c/.*,,')
+b_inode=$(ls -i c/b|sed 's,c/.*,,')
 test "$a_inode" = "$b_inode" || fail=1
 # --------------------------------------
 
@@ -83,7 +83,7 @@ rm -rf a b c d
 touch a; chmod 731 a
 umask 077
 cp -a --no-preserve=mode a b
-mode=`ls -l b|cut -b-10`
+mode=$(ls -l b|cut -b-10)
 test "$mode" = "-rwx------" || fail=1
 umask 022
 # --------------------------------------
diff --git a/tests/cp/link-symlink b/tests/cp/link-symlink
index 97fbf4b9b..57bc9c715 100755
--- a/tests/cp/link-symlink
+++ b/tests/cp/link-symlink
@@ -25,7 +25,7 @@ touch file
 ln -s file link || framework_failure_
 touch -m -h -d 2011-01-01 link ||
   skip_ "Your system doesn't support updating symlink timestamps"
-case `stat --format=%y link` in
+case $(stat --format=%y link) in
   2011-01-01*) ;;
   *) skip_ "Your system doesn't support updating symlink timestamps" ;;
 esac
@@ -33,7 +33,7 @@ esac
 # link.cp is probably a hardlink, but may also be a symlink
 # In either case the timestamp should match the original.
 cp -al link link.cp
-case `stat --format=%y link.cp` in
+case $(stat --format=%y link.cp) in
   2011-01-01*) ;;
   *) fail=1 ;;
 esac
diff --git a/tests/cp/no-deref-link1 b/tests/cp/no-deref-link1
index 8600b8e0a..c2a565793 100755
--- a/tests/cp/no-deref-link1
+++ b/tests/cp/no-deref-link1
@@ -34,6 +34,6 @@ cp -d a/foo b 2>/dev/null
 # Fail this test if the exit status is not 1
 test $? = 1 || fail=1
 
-test "`cat a/foo`" = $msg || fail=1
+test "$(cat a/foo)" = $msg || fail=1
 
 Exit $fail
diff --git a/tests/cp/no-deref-link2 b/tests/cp/no-deref-link2
index 96d444fdf..584029954 100755
--- a/tests/cp/no-deref-link2
+++ b/tests/cp/no-deref-link2
@@ -34,6 +34,6 @@ cp -d a b 2>/dev/null
 # Fail this test if the exit status is not 1
 test $? = 1 || fail=1
 
-test "`cat a`" = $msg || fail=1
+test "$(cat a)" = $msg || fail=1
 
 Exit $fail
diff --git a/tests/cp/no-deref-link3 b/tests/cp/no-deref-link3
index 629f2ae8d..5f63f2699 100755
--- a/tests/cp/no-deref-link3
+++ b/tests/cp/no-deref-link3
@@ -31,6 +31,6 @@ cp -d a b 2>/dev/null
 # Fail this test if the exit status is not 1
 test $? = 1 || fail=1
 
-test "`cat a`" = $msg || fail=1
+test "$(cat a)" = $msg || fail=1
 
 Exit $fail
diff --git a/tests/cp/parent-perm-race b/tests/cp/parent-perm-race
index 4eb79bb47..41486fcb1 100755
--- a/tests/cp/parent-perm-race
+++ b/tests/cp/parent-perm-race
@@ -48,7 +48,7 @@ do
     echo foo
   ) >$attr/fifo
 
-  ls_output=`cat d/$attr.ls` || fail=1
+  ls_output=$(cat d/$attr.ls) || fail=1
   case $attr,$ls_output in
   ownership,d???--[-S]--[-S]* | \
   mode,d????-??-?* | \
diff --git a/tests/cp/perm b/tests/cp/perm
index 2e6126d62..eb3925da2 100755
--- a/tests/cp/perm
+++ b/tests/cp/perm
@@ -49,8 +49,8 @@ for u in 31 37 2; do
 
             case "$cmd:$force:$existing_dest" in
               cp:*:yes)
-                _g_perm=`echo rwx|sed 's/[^'$g_perm']/-/g'`
-                _o_perm=`echo rwx|sed 's/[^'$o_perm']/-/g'`
+                _g_perm=$(echo rwx|sed 's/[^'$g_perm']/-/g')
+                _o_perm=$(echo rwx|sed 's/[^'$o_perm']/-/g')
                 expected_perms=-rw-$_g_perm$_o_perm
                 ;;
               cp:*:no)
diff --git a/tests/cp/preserve-gid b/tests/cp/preserve-gid
index 355db4d87..6f371c3fb 100755
--- a/tests/cp/preserve-gid
+++ b/tests/cp/preserve-gid
@@ -39,7 +39,7 @@ t0() {
   g=$1; shift
   rm -f b || exit 1
   "$@" "$f" b || exit 1
-  s=`stat -c '%u %g' b`
+  s=$(stat -c '%u %g' b)
   if test "x$s" != "x$u $g"; then
     # Allow the actual group to match that of the parent directory
     # (it was set to 0 above).
diff --git a/tests/cp/preserve-link b/tests/cp/preserve-link
index df1d8c53f..5f069af7c 100755
--- a/tests/cp/preserve-link
+++ b/tests/cp/preserve-link
@@ -68,7 +68,7 @@ create_target_tree()
 
 # Note we repeat this, creating either one of
 # two hard linked files from source in the dest, so as to
-# test both paths in `cp` for creating the hard links.
+# test both paths in $(cp) for creating the hard links.
 # The path taken by cp is dependent on which cp encounters
 # first in the source, which is non deterministic currently
 # (I'm guessing that results are sorted by inode and
diff --git a/tests/cp/r-vs-symlink b/tests/cp/r-vs-symlink
index 15616ffd7..e96c58425 100755
--- a/tests/cp/r-vs-symlink
+++ b/tests/cp/r-vs-symlink
@@ -32,7 +32,7 @@ ln -s no-such-file no-file || framework_failure_
 cp -r no-file junk 2>/dev/null || fail=1
 
 cp -r slink bar 2>/dev/null || fail=1
-set x `ls -l bar`; shift; mode=$1
+set x $(ls -l bar); shift; mode=$1
 case $mode in
   l*) ;;
   *) fail=1;;
diff --git a/tests/cp/same-file b/tests/cp/same-file
index d5abfe82b..dbd4d01b6 100755
--- a/tests/cp/same-file
+++ b/tests/cp/same-file
@@ -111,7 +111,7 @@ for args in 'foo symlink' 'symlink foo' 'foo foo' 'sl1 sl2' 'foo hardlink'; do
         # the destination is a copy.
         for f in $args; do
           if test -f $f; then
-            case "`cat $f`" in
+            case "$(cat $f)" in
               "$contents") ;;
               *) echo cp FAILED;;
             esac
diff --git a/tests/cp/sparse b/tests/cp/sparse
index f1633ae0e..a55202877 100755
--- a/tests/cp/sparse
+++ b/tests/cp/sparse
@@ -24,14 +24,14 @@ require_sparse_support_
 # It has to be at least 128K in order to be sparse on some systems.
 # Make its size one larger than 128K, in order to tickle the
 # bug in coreutils-6.0.
-size=`expr 128 \* 1024 + 1`
+size=$(expr 128 \* 1024 + 1)
 dd bs=1 seek=$size of=sparse < /dev/null 2> /dev/null || framework_failure_
 
 
 cp --sparse=always sparse copy || fail=1
 
 # Ensure that the copy has the same block count as the original.
-test `stat --printf %b copy` -le `stat --printf %b sparse` || fail=1
+test $(stat --printf %b copy) -le $(stat --printf %b sparse) || fail=1
 
 # Ensure that --sparse={always,never} with --reflink fail.
 cp --sparse=always --reflink sparse copy && fail=1
diff --git a/tests/cp/special-bits b/tests/cp/special-bits
index 40795104c..4a00891d9 100755
--- a/tests/cp/special-bits
+++ b/tests/cp/special-bits
@@ -33,18 +33,18 @@ chmod u=rwx,g=rx,o=rx . || framework_failure_
 
 
 cp -p a a2 || fail=1
-set _ `ls -l a`; shift; p1=$1
-set _ `ls -l a2`; shift; p2=$1
+set _ $(ls -l a); shift; p1=$1
+set _ $(ls -l a2); shift; p2=$1
 test $p1 = $p2 || fail=1
 
 cp -p b b2 || fail=1
-set _ `ls -l b`; shift; p1=$1
-set _ `ls -l b2`; shift; p2=$1
+set _ $(ls -l b); shift; p1=$1
+set _ $(ls -l b2); shift; p2=$1
 test $p1 = $p2 || fail=1
 
 setuidgid $NON_ROOT_USERNAME env PATH="$PATH" cp -p c c2 || fail=1
-set _ `ls -l c`; shift; p1=$1
-set _ `ls -l c2`; shift; p2=$1
+set _ $(ls -l c); shift; p1=$1
+set _ $(ls -l c2); shift; p2=$1
 test $p1 = $p2 && fail=1
 
 Exit $fail
diff --git a/tests/cp/symlink-slash b/tests/cp/symlink-slash
index 0b32b9536..95c9cfa04 100755
--- a/tests/cp/symlink-slash
+++ b/tests/cp/symlink-slash
@@ -24,7 +24,7 @@ mkdir dir || framework_failure_
 ln -s dir symlink || framework_failure_
 
 cp -dR symlink/ s || fail=1
-set `ls -l s`
+set $(ls -l s)
 
 # Prior to fileutils-4.0q, the following would have output ...'s -> dir'
 # because the trailing slash was removed unconditionally (now you have to