Difference between revisions of "Bash for loop"

Revision as of 14:13, 30 August 2021

Example:

 for i in {1..5}
 do
   echo "Welcome $i times"
 done

using variable start and end parameters

 
NUM=10
for (( i=2; i<=$NUM; i++ ))
  do 
    printf "$i "
  done

output
2 3 4 5 6 7 8 9 10

portable for loop (for older bash versions)

for i in `seq 10`
do
   echo "the i is $i"
done

for VARIABLE in 1 2 3 4 5 .. N
do
  command1
  command2
  commandN
done

OR

for VARIABLE in file1 file2 file3
do
  command1 on $VARIABLE
  command2
  commandN
done

OR

for OUTPUT in $(Linux-Or-Unix-Command-Here)
do
  command1 on $OUTPUT
  command2 on $OUTPUT
  commandN
done

C style for variable usage

for (( i = 0; i <= $length; i++ )) 
  do 
       echo "do something right $i"
  done