PipeRead portability

[Dominique]

I man fvwm, I can read:

ExecUseShell [shell]

Makes the Exec command use the specified shell, or the value of the $SHELL environment variable if no shell is specified, instead of the default Bourne shell (/bin/sh).

and

PipeRead command [quiet]

Causes fvwm to read commands from the output of the command. This command is executed by /bin/sh as if you typed it on the command line.

If this really the case than ExecUseShell will not change the shell used by PipeRead, or do I have to assume than PipeRead will use the same shell than Exec, that is any shell defined by the user with ExecUseShell?

[mimosinnet]

Dominique,

Your question has made me thought on the issue, but I do not have an answer. I have tried this:

ExecUseShell /bin/bash Exec exec gvim DestroyMenu HomeDirMenu AddToMenu HomeDirMenu "Home dir menu" Title PipeRead 'echo "+ $SHELL"'

In this test, gvim and $SHELL gives me zsh (my default shell). In my limited understanding, although ExecUseShell uses the specified shell, it does not change the value of $SHELL. Therefore, gvim and PipeRead are, in my case, using zsh.

Maybe you have a better way of testing it?

Cheers!

[Dominique]

On gentoo, sh is a symlink to bash, so I installed zsh.

If I run in zsh:

P=PROGRAM; PROGRAM=xterm; ${(e)P:+\$$P} &

it launch xterm. With the same line in bash, I get:

bash: ${(e)P:+\$$P} : mauvaise substitution

In fvwm-crystal FvwmConsole:

Exec "P=PROGRAM; PROGRAM=xterm; ${(e)P:+\$$$P}"

give

/bin/sh: P=PROGRAM; PROGRAM=xterm; ${(e)P:+\$$P} : mauvaise substitution

PipeRead "P=PROGRAM; PROGRAM=xterm; \${(e)P:+\\\$\$P}"

give

sh: ${(e)P:+\$$P} : mauvaise substitution

With zsh:

ExecUseShell /bin/xsh Exec "P=PROGRAM; PROGRAM=xterm; ${(e)P:+\$$$P}"
give

zsh:1: command not found: P=PROGRAM; PROGRAM=xterm;

and

Exec "P=PROGRAM; PROGRAM=xterm; \${(e)P:+\\\$\$P}"

give

zsh:1: command not found: P=PROGRAM; PROGRAM=xterm; ${(e)P:+\$$P}

I am in zsh, but the command line is not working. I don’t understand why.

PipeRead "P=PROGRAM; PROGRAM=xterm; \${(e)P:+\\\$\$P}"

give

sh: ${(e)P:+\$$P} : mauvaise substitution

I am in sh, so ExecUseShell doesn’t seam to influence on PipeRead.

But it is more confusing. If I put the command line in a script without shebang (#!/bin/some_shell) and run it with Exec:

Exec $[HOME]/bin/testshell

give

/home/dom/bin/testshell: ligne1: ${(e)P:+\$$P} : mauvaise substitution

with ExecUseShell equal to both sh and zsh.

[thomasadam]

@Dominique

If this really the case than ExecUseShell will not change the shell used by PipeRead…

Correct. ExecUseShell only affects the Exec command.

– Thomas Adam