Executing command at the end of script

Question

I want copy some files, but I want to wait executing the copy commands untill the end of the script. The reason for this is I can expect a user input to interrupt the script halfway, and I don't won't a partially copied directory.

Is there any way I can wait to execute specific commands until exit 0 is seen in the same program?

#!/bin/bash
for f in 'find something/ -newer something_else -type f'; do
   #Expecting user input interruption
   cp "$f" . #I want to wait executing this
done

if [ -f something_else ]; then
   exit 0 #I want it executed here
else 
   exit 1
fi

Can control flow through the script be changed so that copying happens after exit 1 is potentially executed? Also, don't loop over the result of find, and remember to double-quote your variable expansions. — Kusalananda, Mar 03 '18 at 12:11
I want the copy commands to be determined inside the loop, but be executed later, because I take user input to determine the exit status during the loop. — Martin, Mar 03 '18 at 12:17
See the question Why is looping over find's output bad practice? — Kusalananda, Mar 03 '18 at 12:19

Kusalananda · Accepted Answer · 2018-03-04T11:12:07.847

0

The easiest solution would be to do the copying later:

#!/bin/bash

# something something script stuff

[ ! -f somefile ] && exit 1

find something -type f -newer somefile -exec cp {} . ';'

If you want the user to confirm each copy, use -ok instead of -exec in find:

find something -type f -newer somefile -ok cp {} . ';'

To first loop over the file to create a list of files to copy, asking the user for input for each file, and then perform the copy:

copy_these=$(mktemp)

find something -type newer somefile \
    -exec bash -c '
        read -p "Copy $0? [y/n/q]: "
        case "$REPLY" in
            [yY]*) printf "%s\n" "$0" ;;
            [qQ]*) exit 1 ;;
        esac' {} ';' >"$copy_these"

# do other stuff

# then copy the files

xargs cp -t . <"$copy_these"

rm -f "$copy_these"

Note that this assumes that all filenames are well behaved (no newlines), and that GNU cp is used.

edited Mar 04 '18 at 11:12

answered Mar 03 '18 at 12:16

Kusalananda

333,661

Interesting. The -ok option is very useful! Can I costomize the message, and options for the prompt? I would like to have a Yes), No), Quit) option in my case. – Martin Mar 04 '18 at 10:53
Also I still have the challenge that I want the command to be executed in the end of the loop. If the user exists the program while it's running I don't want to copy half of the files. – Martin Mar 04 '18 at 10:55
@Martin It sounds like you'd rather have the loop actually produce a file list and that you later want to copy these. Am I correct? – Kusalananda Mar 04 '18 at 11:01
Yes! You are correct. Sorry for not being precise on what I'm trying to do. – Martin Mar 04 '18 at 11:13
Yes. You nailed it! This is exactly what I was trying. Thanks – Martin Mar 04 '18 at 11:19
Hmm, couldn't we use printf "%s\0" "$0" and xargs -0? – ilkkachu Mar 04 '18 at 11:37
@ilkkachu Yes we could. – Kusalananda Mar 04 '18 at 11:58

Executing command at the end of script

1 Answers1