what it means: exec `ksh -c “echo /usr/bin/expectk \”$0\“ — $*”`

Question

In my company, there are a lot of maintain scripts. I found one start like with:

#!/bin/sh
# the next line restarts using expectk \
exec `ksh -c "echo /usr/bin/expectk \"$0\" -- $*"`

But I don't understand why and how it restarts using expectk.

Anyone help?

Answer 1

That command looks way more complicated than it needs to be. Essentially what its doing (and could be shortened down to) is

#!/bin/sh
exec /usr/bin/expectk $0 -- $*

Your script is execing the output of the echo command. The rewritten version above removes the echo and just does the exec directly. However the better way to do it is

#!/bin/sh
exec /usr/bin/expectk "$0" -- "$@"

This fixes issues that would pop up if any of the arguments to the script contained spaces.