Advanced Bash−Scripting Guide

Advanced Bash−Scripting Guide
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# Same loop, but substituting 'break' for 'continue'.
a=0
while [ "$a" −le "$LIMIT" ]
do
a=$(($a+1))
if [ "$a" −gt 2 ]
then
break # Skip entire rest of loop.
fi
echo −n "$a "
done
echo; echo; echo
exit 0
The break command may optionally take a parameter. A plain break terminates only the innermost
loop in which it is embedded, but a break N breaks out of N levels of loop.
Example 10−21. Breaking out of multiple loop levels
#!/bin/bash
# break−levels.sh: Breaking out of loops.
# "break N" breaks out of N level loops.
for outerloop in 1 2 3 4 5
do
echo −n "Group $outerloop: "
for innerloop in 1 2 3 4 5
do
echo −n "$innerloop "
if [ "$innerloop" −eq 3 ]
then
break # Try break 2 to see what happens.
# ("Breaks" out of both inner and outer loops.)
fi
done
echo
done
echo
exit 0
The continue command, similar to break, optionally takes a parameter. A plain continue cuts short
the current iteration within its loop and begins the next. A continue N terminates all remaining
iterations at its loop level and continues with the next iteration at the loop N levels above.
Chapter 10. Loops and Branches 115