Shell – Access the most recent file in (alphabetically sorted) directory

command linefilesshelltimestampswildcards

I'm trying to open a file with vim from the command line, the file is in a directory filled with automatically generated files that are prepended with a time stamp. Since I don't know the time stamps off the top of my head, I would just like to open the most recent one in the directory (also the last one in the list alphabetically).

vim ./my_dir/<last_item>

Is there a way to do this?

Best Answer

This is really a job for zsh.

vim my_dir/*(om[1])

The bits in parentheses are glob qualifiers. The * before is a regular glob pattern, for example if you wanted to consider only log files you could use *.log. The o glob qualifier changes the order in which the matches are sorted; om means sort by modification time, most recent first. The [ glob qualifier means to only return some of the matches: [1] returns the first match, [2,4] return the next three, [-2,-1] return the last two and so on. If the files have names that begin with their timestamp, *([1]) will suffice.

In other shells, there's no good way to pick the most recent file. If your file names don't contain unprintable characters or newlines, you can use

vim "$(ls -t mydir | head -n 1)"

If you want to pick the first or last file based on the name, there is a fully reliable and portable method, which is a bit verbose for the command line but perfectly serviceable in scripts.

set -- mydir/*
first_file_name=$1
eval "last_file_name=\${$#}"

Related Solutions

Shell – delete old log files except the last one (alphanumerically sorted)

find /home/foo -maxdepth 1 -iname log\* -type f -mmin +1800 |
  sort | head -n -1 | xargs rm

Or if you want to use mtime instead of the filename:

find /home/foo -maxdepth 1 -iname log\* -type f -mmin +1800 -exec ls -t {} + |
  tail -n +2 | xargs rm

From @Stephane's comments, a more robust approach would be to do:

IFS=$'\n'
set -f
rm $(
  find /home/foo -maxdepth 1 -iname log\* ! -name $'*\n*' -type f -mmin +1800 |
  sort | head -n -1 )

Or for POSIX shell (still requires GNU tools):

IFS='
'
ex_newline='*
*'
set -f
rm $(
  find /home/foo -maxdepth 1 -iname log\* ! -name "$ex_newline" -type f -mmin +1800 |
  sort | head -n -1 )

A single (robust) pipeline can be used with a recent version of GNU sed/sort (and GNU find as with all of the above):

find /home/foo -maxdepth 1 -iname log\* -type f -mmin +1800 -print0 |
  sort -z | sed -z '$d' | xargs -0 rm

linux command-line files tmp – How to Access Temporary File After Creation

I've ran into this problem when examining behavior of a particular application I didn't trust. The application would create and later delete its temp files. kenorb's solution is good, however using cat can lead to race condition( that is a file may be removed while cat is working, so partial data only is retrieved).

A lower chance of race condition can be done with creating a hard-link to the file itself. greping and creating hard link can be combined via awk. Thus what I've came up with is the following;

inotifywait -e create -m --format "%w/%f" /tmp/suspicious_dir/ 2>&1 | 
awk 'NR>2{n=split($0,a,"/");system("ln "$0" /tmp/hardlink_to_"a[n]);}'

Since we're using -e create flag , we're only interested in temporary files that are going to be immediately created, and the output format gives us the full path to created temp file. Ignoring first two lines of output via NR>2. For every reported file, there will be created a hard link in form /tmp/hardlink_to_<original filename>

Best Answer

Related Solutions

Shell – delete old log files except the last one (alphanumerically sorted)

linux command-line files tmp – How to Access Temporary File After Creation

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