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Justin
Asked: 2014-12-11 13:23:37 +0800 CST

Checking for a file and whether it is readable and writable

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I'm trying to write a script that will look for a certain .txt file saved to my desktop. I want the script to be able to check if this file exists and then check to see if it is readable and writable.

Any hints?

bash

2 Answers

  1. You needn't check if it exists, the checks for read and write permissions are enough:

    From help test, a selection of relevant tests:

    -a FILE        True if file exists.
-e FILE        True if file exists.
-f FILE        True if file exists and is a regular file.
-r FILE        True if file is readable by you.
-s FILE        True if file exists and is not empty.
-w FILE        True if the file is writable by you.

    So you can try:

    FILE="/path/to/some/file"

if [[ -r $FILE && -w $FILE ]]; then
  # do stuff
else
  # file is either not readable or writable or both
fi
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  2. test -r file.txt -a -w file.txt
echo $?

    The return code is 0 if it is both readable and writeable.

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