CODEWITHSUNDEEP
linuxbashshellunixposix
nodakai
nodakai

Reputation: 8021

Unix shell scripting: pass shell options (-x etc.) to nested scripts

How can I run nested shell scripts with the same option? For example,

parent.sh

#!/bin/sh
./child.sh

child.sh

#!/bin/sh
ls

How can I modify parent.sh so that when I run it with sh -x parent.sh, the -x option is effective in child.sh as well and the execution of ls is displayed on my console?

I'm looking for a portable solution which is effective for rare situations such as system users with /bin/false as their registered shell. Will the $SHELL environment variable be of any help?

Clarification: I sometimes want to call parent.sh with -x, sometimes with -e, depending on the situation. So the solution must not involve hard-coding the flags.

Upvotes: 5

Views: 792

Answers (2)

Laser
Laser

Reputation: 6960

it's looks like a hack and seems it's not the best way.
But it will do exact what you want

One of the ways how you can do it - it's to create aliases to create wrappers for sh:

alias saveShell='cp /bin/sh $some_safe_place'

alias shx='cp $some_safe_place /bin/x_sh; rm /bin/sh; echo "/bin/x_sh -x $@" > /bin/sh; chmod 755 /bin/sh '

alias she='cp $some_safe_place /bin/e_sh; rm /bin/sh; echo "/bin/e_sh -e $@" > /bin/sh; chmod 755 /bin/sh '
alias restoreShell='cp  $some_safe_place /bin/sh'

How to Use:
run saveShell and then use shx or she , if you would change -x on -e run restoreShell and then run shx or she run script as usually sh ./parent.sh

BE VERY CAREFUL WITH MOVING SH

Other solution replace #!/bin/sh to #!/bin/sh -x or #!/bin/sh -e with sed in all sh files before running script.

Upvotes: 0

Nicolae
Nicolae

Reputation: 451

If you use bash, i can recommend the following:

#!/bin/bash
export SHELLOPTS
./child.sh

You can propagate as many times as you need, also you can use echo $SHELLOPTS in every script down the line to see what is happening and how options are propagated if you need to understand it better.

But for /bin/sh it will fail with /bin/sh: SHELLOPTS: readonly variable because of how POSIX is enforced on /bin/sh in various systems, more info here: https://lists.gnu.org/archive/html/bug-bash/2011-10/msg00052.html

Upvotes: 3

Related Questions