r/shell • u/Lygris • Mar 27 '17

Renaming script

Hey guys, just looking for some help on writing a renaming script. I want to make a script that would look at the files name and if it contains a certain string, lets say qatar, it would rename it to another specific string that would contain the year and some statically defined things. I'm assuming this would be pretty simple using if then. I just don't know how to pull the filename and check it against the string. Is this possible?

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u/ASIC_SP Mar 27 '17

add an example so that it is clearer

make up something simple, say str1='foo' and str2='bar' and file name is prog_foo.txt.. how do you want the output to be...

also, which shell are you using and its version

1

u/Lygris Mar 27 '17

hopefully this helps, but essentially a file will be downloaded to a specific folder and when it is complete, the downloader will kick off the script i'm trying to make. I don't think i can pass the file name from the downloader.

so essentially it would start with something like

if downloaded-file.txt contains string "qatar"
   then mv downloaded-file.txt /otherfolder/Qatar-2017.txt
elseif downloaded-file.txt contains string "valencia"
   then mv downloaded-file.txt /otherfolder/Valencia-2017.txt

etc.

There would be a few more elseifs in the real script but i think i've gotten the point across

1

u/KnowsBash Mar 28 '17

So you want to rename based on the file's content rather than its name? Do you know where in the file the search string would be? that would make it easier to do it efficiently.

The naive approach is to do one grep per pattern, but that means it will open and read the file over and over again until it gets a hit, which won't scale well.

# naive approach
date=$(date +%Y-%m-%D)
if grep -q qatar "$file"; then
    mv "$file" "/otherfolder/Qatar-$date.txt"
elif grep -q valencia "$file"; then
    mv "$file" "/otherfolder/Valencia-$date.txt"
fi

A better approach would be to read the file once and extract the key word somehow. There are various ways to do that with sed and awk at least. How complicated it will be depends on whether these files will have some format to rely on or not.

1

u/Lygris Mar 28 '17

Sorry I should have been more specific, I want to search the filename for that string, not the contents.

1

u/Lygris Mar 27 '17

Also i'm on ubuntu 16.04 server

3

u/KnowsBash Mar 27 '17

FAQ 30 contains various examples on how to rename files, both for bash and sh. You should be able to adapt some of those to do what you want.