Variable in Bash Script that keeps it value from the last time running

by

You can’t, but you can use a file to do it

#!/bin/bash

valuefile="/tmp/value.dat"

# if we don't have a file, start at zero
if [ ! -f "$valuefile" ]; then
    value=0

# otherwise read the value from the file
else
    value=$(cat "$valuefile")
fi

# increment the value
value=$((value + 1))

# show it to the user
echo "value: ${value}"

# and save it for next time
echo "${value}" > "$valuefile"

More Related Contents:

  1. How can I store a command in a variable in a shell script?
  2. sh: 1: Syntax error: "(" unexpected error
  3. How do I write a bash script to restart a process if it dies?
  4. How to compare two strings in dot separated version format in Bash?
  5. Use Expect in a Bash script to provide a password to an SSH command
  6. How do I write standard error to a file while using “tee” with a pipe?
  7. How to declare 2D array in bash
  8. Raise error in a Bash script
  9. Separately redirecting and recombining stderr/stdout without losing ordering
  10. Print a file, skipping the first X lines, in Bash [duplicate]
  11. How can I get unique values from an array in Bash?
  12. Recursively counting files in a Linux directory
  13. How to run a shell script on a Unix console or Mac terminal?
  14. How to get the process ID to kill a nohup process?
  15. equivalent date from GNU to solaris
  16. Run text file as commands in Bash
  17. How can I suppress error messages of a command?
  18. Shebang line limit in bash and linux kernel
  19. The Bash command :(){ :|:& };: will spawn processes to kernel death. Can you explain the syntax?
  20. How do I run multiple background commands in bash in a single line?
  21. Add a newline only if it doesn’t exist
  22. Multithreading in Bash [duplicate]
  23. Simple Socket Server in Bash?
  24. Difference between shell and environment variables
  25. How do I get the difference between two dates under bash [duplicate]
  26. SUID not working with shell script
  27. Run script with rc.local: script works, but not at boot
  28. Maximum number of Bash arguments != max num cp arguments?
  29. Write a bash shell script that consumes a constant amount of RAM for a user defined time [closed]
  30. Using “$RANDOM” to generate a random string in Bash

Leave a Comment