Thursday, May 3, 2012

HowTo: Skip Bash For Loop

How do I skip bash for loop if certain condition is satisfied under UNIX / Linux / BSD / OS X?

You can do early exit with break statement inside the for loop. You can exit from within a FOR loop using break using the following syntax:
for i in 1 2 3 4 5 6 8 9 10
do
statements1 #Executed for all values of ''I'', up to a disaster-condition if any.
statements2
if (disaster-condition)
then
break #Abandon the loop.
fi
statements3 # While good and, no disaster-condition.
done
 

Example

In this example, go through all conf file in /etc/ directory and break the loop if /etc/resolv.conf file, else loop will end when all files are checked and it will display not found message:
#!/bin/bash
found=0
for i in /tmp/*.conf
do
if [ "$i" == "resolv.conf" ]
then
echo "resolv.conf found in /etc"
found=1
break
fi
done
if [ $found -eq 0 ]
then
echo "resolv.conf not found in /etc"
fi
 

No comments:

Post a Comment