Is it possible to reference the most recently modified file in a command line argument?

Question

I frequently download PDF files with heinous numeric file names from my browser. These automatically go into ~/Downloads. Ideally I would like to just be able to open these files with:

evince "the most recently modified file"

without having to open ~/Downloads to find the file name.

Is there a simple way to specify "the most recently modified file" in bash?

NOTE: I know that it is possible to do this, but ideally I am looking for a solution that would be simpler than ls -t'ing ~/Downloads to check the name.

Answer 1

evince "$(ls -t | head -n1)"

While it will handle spaces, tabs, and (I believe) printing specials, it will break if the filename contains a newline, and possibly on some other non-printing characters.

Answer 2

This is a more correct and robust approach than ls -t, at the cost of some additional complexity.

Setup

Add a short shell script (code below) to your $PATH. ~/bin is a good place for it.

Remember to make sure

• the script is executable chmod +x ~/bin/script_name
• ~/bin is in your $PATH

Usage

Pass the command you want to run on the newest file in ~/Download to last_download.

Examples

Assuming you named the script last_download

• last_download (no arguments): runs evince, the default command, on the newest file in ~/Downloads
• last_download mplayer: runs mplayer on the newest file in ~/Downloads
• last_download cp -t ~/Desktop: copies the newest file in ~/Downloads to ~/Desktop

Code

#!/bin/sh
# Usage: last_download [cmd [options]...]

newest=
dir=~/Downloads

# default command
if [ $# -eq 0 ]; then
        set -- evince;
fi

# find newest file
for f in "$dir"/*; do
        if [ -z "$newest" ] || [ "$f" -nt "$newest" ]; then
                newest="$f"
        fi
done
if ! [ -e "$newest" ]; then
        exit 1
fi

# run command on newest file
"$@" "$newest"

---

^{Note: The script only looks in ~/Download but it would not be hard to generalize it to support any directory, in which case a name change would also be warranted.}

Answer 3

exec zsh
evince ~/Downloads/*.pdf(om[1])

or if you don't want to switch to zsh

cd ~/Downloads
zsh -c 'evince ./*.pdf(om[1])'

The bits between parentheses are glob qualifiers. om changes the order on globs to use the modification time rather than the name (newest first). [1] means to use only the first match.

For more information, see this answer to "How do I filter a glob in zsh".

Answer 4

You can use a modified find_date_sorted:

last_download() {
    while IFS= read -r -d '' -u 9
    do
        cut -d ' ' -f 3- <<< "$REPLY"
        break
    done 9< <(find ~/Downloads -maxdepth 1 -type f -printf '%TY-%Tm-%Td %TH:%TM:%TS %p\0' | sort -rz)
}

It'll work with any filenames. To open the file:

evince "$(last_download)"

Answer 5

No, and even if there were, you couldn't be sure some system log won't usually be the most recently updated file.

Kevin's answer (he beat me to it) works if you just want to avoid manually opening ~/Downloads.