How can i move/group specific folders in bash? - linux

Question

I have a folder structure like the following:
2020-123-1
2020-123-2
2020-123-3
2020-124-1
2020-124-2
...
I need to create folders from the first 2 numbers and omit whatever follows the second dash (-). Then I need to put the prior folders under the newly created ones with the correct name.
2020-123
->2020-123-1
->2020-123-2
->2020-123-3
2020-124
->2020-124-1
->2020-124-2
I tried to write a script in bash like this:
ls -d */ > folder.txt
cut -f1,2 -d"-" folder.txt |cut -f1 -d"/" |sort|uniq > mainfolder.txt
while read line; do mkdir $line ; done < mainfolder.txt
while read line; do mv $(cut -f1,2 -d"-" $line) $line/ ; done < folder.txt
I couldn't make the last line work, I know it has issues.

Answer 1

Actually, you don't have to parse the directory names and build the hierarchy. You can make use of the -p option of mkdir, thus, an awk one-liner will do the job:
awk -F'-' '{top=$1 FS $2;printf "mkdir -p %s; mv %s %s\n",top, $0, top}' dir.txt
The output with your example:
mkdir -p 2020-123; mv 2020-123-1 2020-123
mkdir -p 2020-123; mv 2020-123-2 2020-123
mkdir -p 2020-123; mv 2020-123-3 2020-123
mkdir -p 2020-124; mv 2020-124-1 2020-124
mkdir -p 2020-124; mv 2020-124-2 2020-124
Note
This one-liner just print the commands without executing them, you just pipe the output to |sh if everything looks fine. Examine the output commands, change the printf format/values for adjustment.
I didn't quote the filenames, since your example doesn't contain any special chars. Do it if it is in the case.

Answer 2

So the final script is as follows:
ls -d */ | cut -f1 -d"/" > folder.txt
awk -F'-' '{top=$1 FS $2;printf "mkdir -p %s; mv %s %s\n",top, $0, top}' folder.txt |sh

Answer 3

In pure bash:
#!/bin/bash
for src in *-*-*; do
destdir=${src%-*}
[[ -d $destdir ]] || mkdir "$destdir" || exit
# This just prints out the command that will be called.
# Remove the "echo" in actual script after making sure it will run as intented
echo mv "$src" "$destdir"
done
In the script above it is assumed that each file name to be moved contains exactly two dashes. If it can contain two or more dashes then the destdir=${src%-*} line should be replaced with these two lines:
suffix=${src#*-*-}
destdir=${src%"-$suffix"}
For detailed information read the "shell parameter expansion" section in bash reference.
Additionally, a good read article is: Why you shouldn't parse the output of ls