Behaviour of csh single quote changed between RHEL4 and RHEL5

Solution Verified - Updated -


  • Red Hat Enterprise Linux 5
  • tcsh-6.14-17.el5.x86_64


  • 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.


  • Set "echo_style=bsd" fixes the problem in RHEL-5
    ~]$ echo '\test'
    ~]$ set echo_style=bsd
    ~]$ echo '\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 the echo_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 $echo_style
  • On RHEL-5
    ~]$ echo $echo_style


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