Use ‘echo’ safely with ‘\’ or leading ‘-’

POSIX says that ‘echo FOO’ produces implementation-defined output
if FOO contains leading ‘-’, or ‘\’ anywhere, so don’t assume GNU
behavior in that case.
* Makefile.in (removenullpaths): Remove.
(epaths-force): Rewrite to avoid the need for ‘echo’.
(install-etc): Be clearer about escaping the shell metacharacters
‘\’ and ‘$’.
* Makefile.in (install-arch-indep, install-etcdoc):
* admin/charsets/mapconv, admin/merge-gnulib, admin/merge-pkg-config:
* admin/quick-install-emacs, build-aux/gitlog-to-emacslog:
* configure.ac, lib-src/rcs2log, make-dist:
* src/Makefile.in (lisp.mk):
Don’t assume ‘echo’ outputs ‘\’ and leading ‘-’ unscathed.
For example, use ‘printf '%s\n' "$foo"’ rather than ‘echo "$foo"’
if $foo can contain arbitrary characters.
* lisp/Makefile.in (TAGS): Use ‘ls’, not ‘echo’, to avoid ‘\’ issues.
* doc/lispref/two-volume.make (vol1.pdf):
* test/etags/make-src/Makefile (web ftp publish):
Use ‘printf’ rather than ‘echo -e’.

1 files changed, 11 insertions, 9 deletions

diff --git a/lib-src/rcs2log b/lib-src/rcs2log
index d1bd3693183..4ee303d03a1 100755
--- a/lib-src/rcs2log
+++ b/lib-src/rcs2log
@@ -130,7 +130,8 @@ do
                 case $1 in
                 -n)     case ${2?}${3?}${4?} in
                         *"$tab"* | *"$nl"*)
-                                echo >&2 "$0: -n '$2' '$3' '$4': tabs, newlines not allowed"
+                                printf '%s\n' >&2 \
+                                  "$0: -n '$2' '$3' '$4': tabs, newlines not allowed"
                                 exit 1;;
                         esac
                         login=$2
@@ -140,7 +141,7 @@ do
                         # If $2 is not tab-separated, use colon for separator.
                         case ${2?} in
                         *"$nl"*)
-                                echo >&2 "$0: -u '$2': newlines not allowed"
+                                printf '%s\n' >&2 "$0: -u '$2': newlines not allowed"
                                 exit 1;;
                         *"$tab"*)
                                 t=$tab;;
@@ -149,7 +150,7 @@ do
                         esac
                         case $2 in
                         *"$t"*"$t"*"$t"*)
-                                echo >&2 "$0: -u '$2': too many fields"
+                                printf '%s\n' >&2 "$0: -u '$2': too many fields"
                                 exit 1;;
                         *"$t"*"$t"*)
                                 uf="[^$t]*$t" # An unselected field, followed by a separator.
@@ -161,7 +162,7 @@ do
                                         expr "X$2" : "$uf$uf$sf"
                                 `;;
                         *)
-                                echo >&2 "$0: -u '$2': not enough fields"
+                                printf '%s\n' >&2 "$0: -u '$2': not enough fields"
                                 exit 1;;
                         esac
                         shift;;
@@ -186,9 +187,9 @@ do
         --version)
                 set $Id
                 rcs2logVersion=$3
-                echo >&2 "rcs2log (GNU Emacs) $rcs2logVersion$nl$Copyright"
+                printf '%s\n' >&2 "rcs2log (GNU Emacs) $rcs2logVersion$nl$Copyright"
                 exit 0;;
-        -*)     echo >&2 "Usage: $0 [OPTION]... [FILE ...]$nl$Help"
+        -*)     printf '%s\n' >&2 "Usage: $0 [OPTION]... [FILE ...]$nl$Help"
                 case $1 in
                 --help) exit 0;;
                 *) exit 1;;
@@ -303,7 +304,8 @@ case $rlogfile in
                         esac
                         if test ! -d "$repository"
                         then
-                                echo >&2 "$0: $repository: bad repository (see CVS/Repository)"
+                                printf '%s\n' >&2 \
+                                  "$0: $repository: bad repository (see CVS/Repository)"
                                 exit 1
                         fi
                         pository=$repository;;
@@ -330,7 +332,7 @@ case $rlogfile in
                                 T?*)
                                         rlog_options=-r`expr "$CVSTAG" : 'T\(.*\)'`;;
                                 *)
-                                        echo >&2 "$0: invalid CVS/Tag"; exit 1;;
+                                        printf '%s\n' >&2 "$0: invalid CVS/Tag"; exit 1;;
                                 esac
                         fi;;
                 esac
@@ -595,7 +597,7 @@ case $hostname in
         hostname=`(
                 hostname || uname -n || uuname -l || cat /etc/whoami
         ) 2>/dev/null` || {
-                echo >&2 "$0: cannot deduce hostname"
+                printf '%s\n' >&2 "$0: cannot deduce hostname"
                 exit 1
         }