Call a custom function inside a bash command - linux

Question

I have the following bash script:
#!/bin/bash
find . -maxdepth 1 -mmin +1 -type f -name "240*.ts"
| xargs -L 1 bash -c 'mv "${1}" "$(get_crtime${1} | awk '{print $5}').ts"' \;
The idea is to find files that are older than one minute matching a certain pattern (in my case, files that start with '240') and rename them from their original name (240-1458910816045.ts) to a desired format (15:00:16.ts).
Inside the script I am using get_crtime command which is a custom function included in /etc/bash.bashrc and has the following implementation:
get_crtime() {
for target in "${#}"; do
inode=$(stat -c '%i' "${target}")
fs=$(df "${#}" | awk '{a=$1}END{print a}')
crtime=$(sudo debugfs -R 'stat <'"${inode}"'>' "${fs}" 2>/dev/null |
grep -oP 'crtime.*--\s*\K.*')
printf "%s\t%s\n" "${target}" "${crtime}"
done
}
When I call the function from the shell, like this:
get_crtime 240-1458910816045.ts | awk '{print $5}'
I get the desired output:
15:00:16
Which is a portion from the file creation date.
My problem is when I include the function call inside my initial script I get the following error:
}).ts": -c: line 0: unexpected EOF while looking for matching `)'
}).ts": -c: line 1: syntax error: unexpected end of file
I think this is caused by incorrect invoking of awk, so I thought to remove it and leave just:
find . -maxdepth 1 -mmin +1 -type f -name "240*.ts"
| xargs -L 1 bash -c 'mv "${1}" "$(get_crtime ${1}).ts"' \;
I get the following error, which is more suggestive:
;: get_crtime: command not found
How can I call the custom function inside the bashrc inside the initial command without getting the last error?
Thank you!
The OS is Ubuntu
The shell is bash

Answer 1

You can't use single quotes inside a single-quote delimited script. Look:
$ bash -c 'printf "%s\n" "$(date | awk '{print $0}')"'
-bash})": -c: line 0: unexpected EOF while looking for matching `)'
-bash})": -c: line 1: syntax error: unexpected end of file
$ bash -c 'printf "%s\n" "$(date | awk "{print \$0}")"'
Fri, Mar 25, 2016 8:59:31 AM
I'm not recommending you use double quotes around your awk script though - create a script to do the mv, etc. for you or figure out some other way to implement it that'll solve your function access problem too.

Answer 2

In this example, used modification time of file, which can be get by stat -c '%y'. The xargs -I param creates possibility to place file name two times, first for stat, second for mv. Then using Parameter Expansion bash features to extract only time from human readable stat output:
find . -maxdepth 1 -mmin +1 -type f -name "240*.ts" | \
xargs -I_ bash -c 'MTIME=$(stat -c '%y' "_") && MTIME=${MTIME#* } && mv "_" ${MTIME%.*}.ts'

Answer 3

You need to export the function:
export -f get_crtime
That will make it available to child bash processes (but not to other shells).
Also, as #EdMorton points out, you cannot use single quotes inside a single quoted-string, which was the problem with the invocation of awk. So you'll need to come up with a different way of quoting the interior argument to awk, or fix get_crtime to just return the string you want.
By the way, you might consider using finds -exec action instead of xargs. That would allow you to use a loop over a number of files, which would be a bit more efficient.
eg.
find . -maxdepth 1 -mmin +1 -type f -name "240*.ts" \
-exec bash -c 'for f in "$#"; do
mv "$f" "$(get_crtime "$f" | awk {print\$5}).ts"
done' _ {} +