CODEWITHSUNDEEP
bashshell
Brian G
Brian G

Reputation: 409

Shell script nested loop

I want to produce a list of files between 14 and 22 April.
The filenames will have the date in the name, e.g. J0018658.WANCL90A.16Apr2014.214001.STD.txt.
I have tried this script.

for i in 14 15 16 17 18 19 20 21 22; do
    for x in *$iApr*.txt; do
      echo "$x"
    done
done

I am using this on AIX and the default shell is ksh. However sh and bash are also available. Here is what works with ksh:

for i in 14 15 16 17 18 19 20 21 22; do
    for x in *${i}Apr*.txt; do
        echo "$x"
    done
done

Here is what works even better with bash:

#!/bin/bash

shopt -s nullglob
for i in {14..22}; do
    for x in *${i}Apr*.txt; do
          echo "$x"
    done
done

Upvotes: 0

Views: 63

Answers (2)

Digital Trauma
Digital Trauma

Reputation: 15986

will try to expand a variable called iApr, which is not what you want.

Instead, try making your inner for loop look like this:

for x in *${i}Apr*.txt; do

Also, your outer loop can be similar to the concept in @anubhava's answer:

for i in {14..22}; do

So the script should look something like this:

#!/bin/bash

shopt -s nullglob
for i in {14..22}; do
    for x in *${i}Apr*.txt; do
          echo "$x"
    done
done

Again, thanks @anubhava for pointing out the necessity of shopt -s nullglob

About #!/bin/sh vs. #!/bin/bash:

If you're running Linux, your /bin/sh is likely simply a symlink to /bin/bash. From the man page:

If bash is invoked with the name sh, it tries to mimic the startup behavior of historical versions of sh as closely as possible, while conforming to the POSIX standard as well.

Upvotes: 3

anubhava
anubhava

Reputation: 784898

You can do:

ls *{14..22}Apr*.txt

OR in BASH:

shopt -s nullglob; echo *{14..22}Apr*.txt

Upvotes: 2

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