You can use bash shell loop (run code or command repeatedly) to run a command 10 times as follows.
there are many ways to run a command N times in bash/ksh/zsh. Use syntax as per your shell.
Syntax
The syntax is:
## run command 10 times for i in {1..10}; do commandNameHere; done ## run script 20 times for i in {1..10}; do /path/to/cache.script.sh; done |
For example, run UNIX date command five times, enter:
for i in {1..5}; do date; done |
You can also use c like bash for loop syntax:
for ((n=0;n<5;n++)) do command1 command2 done |
The for loop syntax for tcsh / csh / ksh and other shell may changes from version to version.
Using while loop
Use the bash/sh/ksh posix based while loop as follows:
## define end value ## END=5 ## print date five times ## x=$END while [ $x -gt 0 ]; do date x=$(($x-1)) done |
repeat for zsh users
If you are using the Z shell (zsh)
repeat N { command } repeat N { /path/to/script } ## print date five times on screen ## repeat 5 { date } |
Say hello to seq command
To print a sequence of numbers one can use the seq command too. The syntax is:
seq LAST
seq FIRST LAST
seq FIRST INCREMENT LASE
seq LAST | xargs command
seq FIRST LAST | xargs command
seq FIRST INCREMENT LASE | xargs command
To just print five number, run:
$ seq 1 5
OR
$ seq 5
Sample outputs:
1 2 3 4 5
Use the xargs command to run the date command five times:
$ seq 1 5 | xargs -I{} date
Sample outputs:
Tue Nov 28 00:32:52 IST 2017 Tue Nov 28 00:32:52 IST 2017 Tue Nov 28 00:32:52 IST 2017 Tue Nov 28 00:32:52 IST 2017 Tue Nov 28 00:32:52 IST 2017
You can use xargs with multiple commands line argument as follows:
$ seq 1 5 | xargs -I{} sh -c "date && sleep 1"
It is also possible to use the parallel command:
$ seq 5 | parallel 'echo {}'
$ seq 5 | parallel 'echo Hello $USER, {} times.'
See man page of the following command for more info:
$ man parallel
$ man xargs
$ man seq
A note about using Perl or Python
You can use python or Perl as follows to run date command 5 times:
#!/usr/bin/perl for $i (1 .. 5) { system("date"); } |
Python example:
#!/usr/bin/python # Run unix date command 3 times import os; for x in range(0,3): os.system("date") |
11 comment
I always forget the list iterator {1..10} syntax for bash. Thanks for the reminder!
Nice and useful article, indeed.
A litte note:
You said “For example, run UNIX date command five times, enter:”
and then shows: for i in {1..10}; do date; done
I mean: five times would be
for i in {1..5}; do date; done
But I know people understood what you’ve said.
Thanks again!
Thanks for the heads up!
Moin,
old style methods:
for i in $(seq 5);do date;done
for i in `seq 1 5`;do date;done
for i in 1 2 3 4 5;do date;done
for i in a b c d orwhatever;do date;done
at last some crazy unuseful (only work with dirs with more than 5 items)
for i in `ls /proc/*|head -n5`;do date;done
which is useful tool, repait command with delay
Hi.
I got this little function in my bash_aliases:
repeat() { local i n; n=$1; shift; for ((i=1; i<=n; i++)); do "$@"; done; }
then you can do # repeat 5 echo hey there
Hi,
I have another way to implement this.
just use seq and xargs
function __my_test { test $# -gt 1 && `seq 0 $1|xargs -i ${*#$1}`; }
Thanks for this :) Whenever I google something for linux/bash help I’m normally taken here XD
seq 20 | xargs commandName
[felmo@localhost ~]$ seq 20 | xargs echo “TEST!”
TEST! 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
this is the output from my fedora 27 terminal… how does this work exactly?
The seq command display numbers from FIRST to LAST. For example print a sequence of numbers between 1 to 5