# Test cases:
# echo '\n' | wc -l prints 1 when OK, 2 when KO
# echo '\t' | grep t > /dev/null has return code 0 when OK, 1 when KO
-# This problem is a weird heritage from SVR4. BSD got it right.
+# This problem is a weird heritage from SVR4. BSD got it right (except that
+# BSD echo interprets '-n' as an option, which is also not desirable).
# Nowadays the problem occurs in 4 situations:
-# - in bash, when the shell option xpg_echo is set,
+# - in bash, when the shell option xpg_echo is set (bash >= 2.04)
+# or when it was built with --enable-usg-echo-default (bash >= 2.0)
+# or when it was built with DEFAULT_ECHO_TO_USG (bash < 2.0),
# - in zsh, when sh-emulation is not set,
# - in ksh (e.g. AIX /bin/sh and Solaris /usr/xpg4/bin/sh are ksh instances,
# and HP-UX /bin/sh and IRIX /bin/sh behave similarly),
# - in Solaris /bin/sh and OSF/1 /bin/sh.
# We try the following workarounds:
# - for all: respawn using $CONFIG_SHELL if that is set and works.
-# - for bash: unset the shell option xpg_echo.
+# - for bash >= 2.04: unset the shell option xpg_echo.
+# - for bash >= 2.0: define echo to a function that uses the printf built-in.
+# - for bash < 2.0: define echo to a function that uses cat of a here document.
# - for zsh: turn sh-emulation on.
+# - for ksh: alias echo to 'print -r'.
# - for ksh: alias echo to a function that uses cat of a here document.
-# - for Solaris /bin/sh: respawn using /bin/ksh and rely on the ksh workaround.
+# - for Solaris /bin/sh and OSF/1 /bin/sh: respawn using /bin/ksh and rely on
+# the ksh workaround.
# - otherwise: respawn using /bin/sh and rely on the workarounds.
# When respawning, we pass --no-reexec as first argument, so as to avoid
# turning this script into a fork bomb in unlucky situations.
exec $CONFIG_SHELL "$0" --no-reexec "$@"
exit 127
fi
-# For bash: unset the shell option xpg_echo.
+# For bash >= 2.04: unset the shell option xpg_echo.
if test -z "$have_echo" \
&& test -n "$BASH_VERSION" \
&& (shopt -o xpg_echo; echo '\t' | grep t > /dev/null) 2>/dev/null; then
shopt -o xpg_echo
have_echo=yes
fi
+# For bash >= 2.0: define echo to a function that uses the printf built-in.
+# For bash < 2.0: define echo to a function that uses cat of a here document.
+# (There is no win in using 'printf' over 'cat' if it is not a shell built-in.)
+if test -z "$have_echo" \
+ && test -n "$BASH_VERSION"; then \
+ if type printf 2>/dev/null | grep / > /dev/null; then
+ # 'printf' is not a shell built-in.
+echo ()
+{
+cat <<EOF
+$*
+EOF
+}
+ else
+ # 'printf' is a shell built-in.
+echo ()
+{
+ printf '%s\n' "$*"
+}
+ fi
+ if echo '\t' | grep t > /dev/null; then
+ have_echo=yes
+ fi
+fi
# For zsh: turn sh-emulation on.
if test -z "$have_echo" \
&& test -n "$ZSH_VERSION" \
&& (emulate sh) >/dev/null 2>&1; then
emulate sh
fi
+# For ksh: alias echo to 'print -r'.
+if test -z "$have_echo" \
+ && (type print) >/dev/null 2>&1; then
+ # A 'print' command exists.
+ if type print 2>/dev/null | grep / > /dev/null; then
+ :
+ else
+ # 'print' is a shell built-in.
+ if (print -r '\told' | grep told > /dev/null) 2>/dev/null; then
+ # 'print' is the ksh shell built-in.
+ alias echo='print -r'
+ fi
+ fi
+fi
+if test -z "$have_echo" \
+ && echo '\t' | grep t > /dev/null; then
+ have_echo=yes
+fi
# For ksh: alias echo to a function that uses cat of a here document.
# The ksh manual page says:
# "Aliasing is performed when scripts are read, not while they are executed.
# Therefore, for an alias to take effect, the alias definition command has
# to be executed before the command which references the alias is read."
# Because of this, we have to play strange tricks with have_echo, to ensure
-# that the top-level statement containing the test start after the 'alias'
+# that the top-level statement containing the test starts after the 'alias'
# command.
if test -z "$have_echo"; then
bsd_echo ()