execline
Software
skarnet.org

The ifte program

ifte performs a conditional alternative.

Interface

In an execlineb script:

     ifte [ -X ] [ -n ] { progthen... } { progelse... } progif...

• ifte reads progthen... and progelse... in two consecutive blocks.
• ifte runs progif... as a child process and waits for it to complete.
• If progif... crashes (i.e. is killed by a signal), ifte prints an error message, then exits 128 plus the number of the signal that killed progif.
• If progif... exits zero, ifte execs into progthen..., else it execs into progelse....

Options

• -X : do not exit if progif crashes; instead, proceed as if the test had returned false.
• -n : negate the test. progthen... will be run iff progif... exits nonzero.

Notes

ifte is a simpler version of ifthenelse. It performs only conditional execution, not instruction sequence.

"ifthenelse { progif } { progthen } { progelse } remainder" is the equivalent of "foreground { ifte { progthen } { progelse } progif } remainder".