if -- Command

Execute a command conditionally
if sequence1 then sequence2 [elif sequence3 then sequence4] ... [else sequence5] fi

The shell  construct if executes  commands conditionally, depending  on the
exit status of the execution of other commands.

First, if executes  the commands in sequence1. If the  exit status is zero,
it  executes  the  commands in  sequence2  and  terminates.  Otherwise,  it
executes the  optional sequence3  if given,  and executes sequence4  if the
exit status  is zero.  It  executes additional elif  clauses similarly.  If
the exit status of each tested command sequence is nonzero, it executes the
optional else part sequence5.

Because the  shell recognizes  a reserved word  only as the  unquoted first
word of a command, each then, elif, else, and fi must either occur unquoted
at the start of a line or be preceded by `;'.

The shell executes if directly.

Example

For an example of this command, see the entry for trap.

See Also

commands,
ksh,
sh,
test

© 2012 by Stephen A. Ness