Scripts

some Bash snippets

Change Working Directory

Switch the Working Directory to the Base Path where the Scripts remains. Helpfull for Includes, Log Files, Relative Path and so on …

#!/usr/bin/env bash
script_path=$(dirname "$0")
cd "$script_path"

Check Return Code

Run a Command, store the Return Code, and check if it was successfull or failed

#!/usr/bin/env sh

check_ret () {
  if [[ "$ret" == "0" ]]; then
    echo "Command terminated sucessfully"
  else
    echo "Command returned an Error: ${ret}"
  fi
}

which bash > /dev/null 2>&1
ret=$?
check_ret $ret


which BASH > /dev/null 2>&1
ret=$?
check_ret $ret

exit 0

Source or Execute

You can Source a Script or Execute it. On Different Shells and on different Operation Systems.

How to Process Large Files … ?

Large is a variable Term, 700 GB is large for me, while it could be a small peace for others.

Assuming you need to count the lines … this simple Task can take minutes !

Size

[user@host /tmp]$ du -sh bigfile
745G bigfile

Wordcount -> 10 min

if you need to count the lines, use the wordcount command and you get the exact number … but you have to wait for minutes, depending in your disk subsystem and the file size of course