HowTo: Use bash For Loop In One Line

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How do I use bash for loop in one line under UNIX or Linux operating systems?

The syntax is as follows to run for loop from the command prompt.

Run Command 5 Times

for i in {1..5}; do COMMAND-HERE; done

OR

 for((i=1;i<=10;i+=2)); do echo "Welcome $i times"; done

Work On Files

for i in *; do echo $i; done

OR

for i in /etc/*.conf; do cp $i /backup; done

Posted by: Vivek Gite

The author is the creator of nixCraft and a seasoned sysadmin, DevOps engineer, and a trainer for the Linux operating system/Unix shell scripting. Get the latest tutorials on SysAdmin, Linux/Unix and open source topics via RSS/XML feed or weekly email newsletter.

10 comment

    1. two commands:
      for i in (); do echo $i ; ls $i; done

      nested for:

      for i in {0..3}; do for j in {0..9}; do echo -n \($i, $j\); echo Is today the $i$j \?; done; done

  4. For the very rare case yout got file names with a leading dash:

    for i in *; do echo $i; done [ will not show files with leading dash ]

    for i in “*”; do echo $i; done [ will show files with leading dash (but not one file per line) ]

  9. Hi, I’m new in bash, please help me somebody. ..
    I have one folder in linux server and in folder has some *.sql file, so I want to execute all the sql in my mysql sequencely one by one. We also want output on my display as well as in log file for every files execution error. Ex. /root/desktop/sql/1_ff_f_update. And 2_*, 3_* so on. Count of the file was change every time so we can not tell u of count of the files….

    If possible help me..
    Thanks in advance. .

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