#7 unbuffer may be incompatible with other versions of tclsh in PATH

[Clint Johnson]

At some point, from CentOS 6.3 to 7.6 (with TCL 8.5), the /usr/bin/unbuffer script was changed to run tclsh, directly, instead /usr/bin/expect

If you have tclsh version 8.6 in PATH, prior to /usr/bin/tclsh (v8.5) the unbuffer command will give an error.
[~/tmp]% unbuffer ls
can't find package Expect
  while executing
"package require Expect"
  (file "/usr/bin/unbuffer" line 6)

expect version 5.45.4 of unbuffer calls ‘tclsh’ without specifying the location of tclsh, depending on $PATH to locate it.
If it had been written ‘exec /usr/bin/tclsh’ instead of ‘exec tclsh’, there would not be a problem.

A work-around, so as to always execute /usr/bin/tclsh, would be to modify /usr/bin/unbuffer in place, or copy to the first folder in PATH, and edit line 4 of the script
4c4
< exec tclsh "$0" ${1+"$@"}

---

exec /usr/bin/tclsh "$0" ${1+"$@"}

Perhaps the full path of tclsh should be specified in the /usr/bin/unbuffer script?

[Clint Johnson]

Correction: Not another version of tclsh but rather a script called tclsh which does something unexpected. If the irregular tclsh occurs in PATH, prior to /usr/bin/tclsh then something unexpected may occur. The remedy, I still think, is to call /usr/bin/tclsh rather than tclsh