shell for loop example

for_loop_example_2.sh

# Redirecting the output of a for 
#    loop to a file .

$ for x in {1..10} ; do echo $x ; done > filesave

$ cat filesave 
1
2
3
4
5
6
7
8
9
10


# Piping the output of a for 
# loop to another program 

$ for var in `date`
> do 
>    echo $var
> done | tr '\n' ' '
Wed Apr 28 17:43:16 EEST 2021
# Execute the date command ,
# its output is 
# Wed Apr 28 17:43:16 EEST 2021
# Whitespace , new lines and 
# tabs are considered word 
# separators , depending 
# on the value of the shell
# IFS variable . IFS stands for 
# Input Field Separator . 
# echo will echo back each word ,
# so the output from the for loop
# should be like this :
# Wed
# Apr
# ...
# Use the translate command , to 
# translate new lines to a white
# space , so the final output 
# of executing the command is 
# Wed Apr 28 17:43:16 EEST 2


# Perform a long computation in the background .
# The result of the computation is saved into
# the file save_result
$ for i in {1..1000000}; do echo i; done >save_result &