Linux Admin - Loop Control

Sometimes (a lot times actually) we will either want to skip loop iteration operation or break out of a loop prior to completion. These operations are performed with the following verbs: continue and break.

continue

#!/bin/bash 
myFile = "myLines.txt" 
while read -a FILENAME; 
   do 
   
   if [ `echo $FILENAME | grep 004` ]; 
      then 
      continue 
   fi 
   
echo $FILENAME 
done < $myFile

The snippet above will skip the 4th line of the text file, then continue script execution.

line001 
line002 
line003 
line005 
line006 
line007 
line008 
line009

break

Break will stop the loop in its entirety rather than skip a single iteration when a condition is met.

#!/bin/bash 
myFile = "myLines.txt"

while read -a FILENAME; 
   do 
   
   if [ `echo $FILENAME | grep 004` ]; 
      then 
         break 
   fi  
   
echo $FILENAME 
done < $myFile

The above script produces the following output.

line001 
line002 
line003