Is there any way to use while loop and grep all together? See my example:

while  [[  !(grep -R -h "${text}" ${path}) ]];

It says:

./test_script.sh: line 1: conditional binary operator expected
./test_script.sh: line 1: expected `)'
./test_script.sh: line 1: syntax error near `-R'
./test_script.sh: line 1: `while  [[  !(grep -R -h "${text}" ${path}) ]];'
  • What exactly you want to achieve ? Any expected output.
    – Pacifist
    Mar 2 '16 at 3:19
  • From this to work ... When grep does not find a specific text wait for another script to try complete its task to add this text and repeat every 10 seconds till its done and text is present...
    – Byakugan
    Mar 2 '16 at 3:21
  1. Don't put commands inside square brackets.  To loop while grep succeeds (i.e., until it fails), just do

    while grep ...
  2. To loop while grep fails (i.e., until it succeeds), do

    while ! grep ...

    with whitespace (i.e., one or more spaces and/or tabs) between the ! and the command.

  3. You should always quote your shell variable references (e.g., "$path") unless you have a good reason not to, and you’re sure you know what you’re doing.  By contrast, while braces can be important, they’re not as important as quotes, so "$text" and "$path" are good enough (you don't need to use "${text}" and "${path}", in this context).

    … unless path might be set to a list of filenames, in which case, see Security implications of forgetting to quote a variable in bash/POSIX shells  — But what if …?

  4. You don't need the semicolon (;) at the end of the while line (unless you put the do after it).  In other words, the while line and the do must be separated by a semicolon and/or one or more newlines.

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