Tjcw fix vtysh for -f -

[tjcw]

Why I did it

I needed vtysh to be able to take input from a pipe, i.e. something like
{
echo list
echo list
} | vtysh -f -

How I did it

I made changes to the file handling in vtysh so that piped input works; the old code had a dependency on the -f value representing a real file and not a pipe, I removed this dependency

How to verify it

Try
{
echo list
echo list
} | docker -i bgp vtysh
to the SONiC shell

Which release branch to backport (provide reason below if selected)

• 201811
• 201911
• 202006
• 202012
• 202106

Description for the changelog

A picture of a cute animal (not mandatory but encouraged)

[ghost]

All CLA requirements met.

[tjcw]

Apologies for forgetting to sign off the commit with '-s'

[tjcw]

@lguohan please review this PR

[tjcw]

@lguohan what is the next step for this PR ? I think it is ready for review and merge, but if you think it needs further developement please let me know what area I should attend to. Thanks ! Chris Ward, IBM.

[tjcw]

@lguohan what is the next step for this PR ? I think it is ready for review and merge, but if you think it needs further developement please let me know what area I should attend to. Thanks ! Chris Ward, IBM.

[tjcw]

@lguohan what is the next step for this PR ? IBM would like it integrated into master so that I do not have to maintain a separate branch.

[linux-foundation-easycla]

• ✅ login: lguohan / name: Guohan Lu (81132ef)
• ❌ - login: @tjcw / name: Chris Ward . The commit (bd93f16, 9614005, 7064638, ee34015, 6e55892, cf79497) is not authorized under a signed CLA. Please click here to be authorized. For further assistance with EasyCLA, please submit a support request ticket.

[lguohan]

is this upstreamed to frr community?

[tjcw]

I am no longer working in this area. I believe the fix would be useful, but I cannot progress it myself. Closing.