Behaviour of csh single quote changed between RHEL4 and RHEL5
Environment
- Red Hat Enterprise Linux 5
- tcsh-6.14-17.el5.x86_64
Issue
- Behaviour on Red Hat Enterprise Linux 4 using csh (RPM: tcsh-6.13-10.el4)
# echo '\this is a test'
\this is a test
- Behaviour on RHEL 5 using csh (RPM: tcsh-6.14-17.el5.x86_64)
#echo '\this is a test'
his is a test
- The string in single quotes should not interpret backslash and the csh in RHEL5 behaviour seems like a bug.
Resolution
- Set "echo_style=bsd" fixes the problem in RHEL-5
~]$ echo '\test'
est
~]$ set echo_style=bsd
~]$ echo '\test'
\test
- The default
echo_style
setting is being auto-detected at compile time and depends on the machine architecture (macros defined in standard headers) which have been changed between RHEL-4 and RHEL-5 releases. The default setting can be easily overridden by setting theecho_style
in one of the startup sourced scripts.
Root Cause
-
The difference is in the default setting of the
echo_style
variable which controls the way the echo treats the escape sequences (see# man csh
for details) -
On RHEL-4
~]$ echo $echo_style
bsd
- On RHEL-5
~]$ echo $echo_style
both
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