How to print a sequence of 100 numbers using shell script or bash shell while loop ?
Today lets see quickly how to print a sequence of 100 numbers using while loop in bash shell on Linux.
Printing sequence of 100 numbers
a. Empty the file. [root@ngelinux001 ~]# echo > a.txt b. echo each number in a file a.txt till 250. To print till 100, we can change "257" with 101. [root@ngelinux001 ~]# i=1; while [ $i -lt 257 ] ; do echo $i >> a.txt; (( i = $i + 1 )) ; done [root@ngelinux001 ~]# wc -l a.txt 257 a.txt [root@ngelinux001 ~]# tail a.txt 247 248 249 250 251 252 253 254 255 256
Understanding the command
[root@ngelinux001 ~]# i=1; while [ $i -lt 257 ] ; do echo $i >> a.txt; (( i = $i + 1 )) ; done
a. Set variable i initial value is 1.
b. Run a look till i is less than 257 i.e. till i=256
c. echo value of i into file “a.txt”
d. Increment the value of i by 1