Shell Command to Get Directory with Least Access Date/Time

How to obtain the absolute path of a file via Shell (BASH/ZSH/SH)?

Use realpath

$ realpath example.txt
/home/username/example.txt

Find files on Windows modified after a given date using the command line

The forfiles command works without resorting to PowerShell. The article is here:

Find files based on modified time

Microsoft Technet documentation: forfiles

For the example above:

forfiles /P <dir> /S /D +12/07/2013

/P The starting path to search
/S Recurse into sub-directories
/D Date to search, the "+" means "greater than" or "since"

How to get the latest file in a folder?

Whatever is assigned to the files variable is incorrect. Use the following code.

import glob
import os

list_of_files = glob.glob('/path/to/folder/*') # * means all if need specific format then *.csv
latest_file = max(list_of_files, key=os.path.getctime)
print(latest_file)

How do I get the directory where a Bash script is located from within the script itself?

#!/usr/bin/env bash

SCRIPT_DIR=$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )

is a useful one-liner which will give you the full directory name of the script no matter where it is being called from.

It will work as long as the last component of the path used to find the script is not a symlink (directory links are OK). If you also want to resolve any links to the script itself, you need a multi-line solution:

#!/usr/bin/env bash

SOURCE=${BASH_SOURCE[0]}
while [ -L "$SOURCE" ]; do # resolve $SOURCE until the file is no longer a symlink
  DIR=$( cd -P "$( dirname "$SOURCE" )" >/dev/null 2>&1 && pwd )
  SOURCE=$(readlink "$SOURCE")
  [[ $SOURCE != /* ]] && SOURCE=$DIR/$SOURCE # if $SOURCE was a relative symlink, we need to resolve it relative to the path where the symlink file was located
done
DIR=$( cd -P "$( dirname "$SOURCE" )" >/dev/null 2>&1 && pwd )

This last one will work with any combination of aliases, source, bash -c, symlinks, etc.

Beware: if you cd to a different directory before running this snippet, the result may be incorrect!

Also, watch out for $CDPATH gotchas, and stderr output side effects if the user has smartly overridden cd to redirect output to stderr instead (including escape sequences, such as when calling update_terminal_cwd >&2 on Mac). Adding >/dev/null 2>&1 at the end of your cd command will take care of both possibilities.

To understand how it works, try running this more verbose form:

#!/usr/bin/env bash

SOURCE=${BASH_SOURCE[0]}
while [ -L "$SOURCE" ]; do # resolve $SOURCE until the file is no longer a symlink
  TARGET=$(readlink "$SOURCE")
  if [[ $TARGET == /* ]]; then
    echo "SOURCE '$SOURCE' is an absolute symlink to '$TARGET'"
    SOURCE=$TARGET
  else
    DIR=$( dirname "$SOURCE" )
    echo "SOURCE '$SOURCE' is a relative symlink to '$TARGET' (relative to '$DIR')"
    SOURCE=$DIR/$TARGET # if $SOURCE was a relative symlink, we need to resolve it relative to the path where the symlink file was located
  fi
done
echo "SOURCE is '$SOURCE'"
RDIR=$( dirname "$SOURCE" )
DIR=$( cd -P "$( dirname "$SOURCE" )" >/dev/null 2>&1 && pwd )
if [ "$DIR" != "$RDIR" ]; then
  echo "DIR '$RDIR' resolves to '$DIR'"
fi
echo "DIR is '$DIR'"

And it will print something like:

SOURCE './scriptdir.sh' is a relative symlink to 'sym2/scriptdir.sh' (relative to '.')
SOURCE is './sym2/scriptdir.sh'
DIR './sym2' resolves to '/home/ubuntu/dotfiles/fo fo/real/real1/real2'
DIR is '/home/ubuntu/dotfiles/fo fo/real/real1/real2'

How to get N files in a directory order by last modified date?

Limit just some files => pipe to Select-Object -first 10
Order in descending mode => pipe to Sort-Object LastWriteTime -Descending
Do not list directory => pipe to Where-Object { -not $_.PsIsContainer }

So to combine them together, here an example which reads all files from D:\Temp, sort them by LastWriteTime descending and select only the first 10:

Get-ChildItem -Force -Recurse -File -Path "C:\Users" -ErrorAction SilentlyContinue | Where-Object { $_.CreationTime.Date -lt (Get-Date).Date } | Sort CreationTime -Descending | Select-Object -First 10 CreationTime,FullName | Format-Table -Wrap

Bash script find if file is created less then X time ago

You can use find command with -mmin option.

if [ `find path/to/file -mmin -60 | wc -c` -gt 0 ]; then
    #found
fi

How to grant permission to users for a directory using command line in Windows?

As of Vista, cacls is deprecated. Here's the first couple of help lines:

C:\>cacls
NOTE: Cacls is now deprecated, please use Icacls.

Displays or modifies access control lists (ACLs) of files

You should use icacls instead. This is how you grant John full control over D:\test folder and all its subfolders:

C:\>icacls "D:\test" /grant John:(OI)(CI)F /T

According do MS documentation:

F = Full Control
CI = Container Inherit - This flag indicates that subordinate containers will inherit this ACE.
OI = Object Inherit - This flag indicates that subordinate files will inherit the ACE.
/T = Apply recursively to existing files and sub-folders. (OI and CI only apply to new files and sub-folders). Credit: comment by @AlexSpence.

For complete documentation, you may run "icacls" with no arguments or see the Microsoft documentation here and here

How do I get current date/time on the Windows command line in a suitable format for usage in a file/folder name?

See Windows Batch File (.bat) to get current date in MMDDYYYY format:

@echo off
For /f "tokens=2-4 delims=/ " %%a in ('date /t') do (set mydate=%%c-%%a-%%b)
For /f "tokens=1-2 delims=/:" %%a in ('time /t') do (set mytime=%%a%%b)
echo %mydate%_%mytime%

If you prefer the time in 24 hour/military format, you can replace the second FOR line with this:

For /f "tokens=1-2 delims=/:" %%a in ("%TIME%") do (set mytime=%%a%%b)

C:> .\date.bat

2008-10-14_0642

If you want the date independently of the region day/month order, you can use "WMIC os GET LocalDateTime" as a source, since it's in ISO order:

@echo off
for /F "usebackq tokens=1,2 delims==" %%i in (`wmic os get LocalDateTime /VALUE 2^>NUL`) do if '.%%i.'=='.LocalDateTime.' set ldt=%%j
set ldt=%ldt:~0,4%-%ldt:~4,2%-%ldt:~6,2% %ldt:~8,2%:%ldt:~10,2%:%ldt:~12,6%
echo Local date is [%ldt%]

C:>test.cmd

Local date is [2012-06-19 10:23:47.048]

Get Folder Size from Windows Command Line

You can just add up sizes recursively (the following is a batch file):

@echo off
set size=0
for /r %%x in (folder\*) do set /a size+=%%~zx
echo %size% Bytes

However, this has several problems because cmd is limited to 32-bit signed integer arithmetic. So it will get sizes above 2 GiB wrong¹. Furthermore it will likely count symlinks and junctions multiple times so it's at best an upper bound, not the true size (you'll have that problem with any tool, though).

An alternative is PowerShell:

Get-ChildItem -Recurse | Measure-Object -Sum Length

or shorter:

ls -r | measure -sum Length

If you want it prettier:

switch((ls -r|measure -sum Length).Sum) {
  {$_ -gt 1GB} {
    '{0:0.0} GiB' -f ($_/1GB)
    break
  }
  {$_ -gt 1MB} {
    '{0:0.0} MiB' -f ($_/1MB)
    break
  }
  {$_ -gt 1KB} {
    '{0:0.0} KiB' -f ($_/1KB)
    break
  }
  default { "$_ bytes" }
}

You can use this directly from cmd:

powershell -noprofile -command "ls -r|measure -sum Length"

¹ I do have a partially-finished bignum library in batch files somewhere which at least gets arbitrary-precision integer addition right. I should really release it, I guess :-)