CODEWITHSUNDEEP
bashfileif-statement
IWIN
IWIN

Reputation: 13

How to check existence of multiple files(giving type extension as parameter) in a folder -using bash

Scenario: I have a set of .txt files inside folder and script is checking whether *.txt files exists or not

Script:

set -x
if [ -f  *.txt ]
then
        echo exist
else
        echo not
fi

Output:

+ '[' -f 1.txt 2.txt ']'
test.sh: line 2: [: 1.txt: binary operator expected
+ echo not
not

Upvotes: 1

Views: 298

Answers (1)

oguz ismail
oguz ismail

Reputation: 50750

-f unary primary takes only one operand. You need to replace [ -f *.txt ] with:

( set +f -- *.txt; test "$*" != '*.txt' || test -f '*.txt' )

This doesn't perform a type check on every matching file but I assume it'll suffice for your case.

  • +f to set is for making sure pathname expansion is not disabled,
  • -- is for marking the end of options,
  • *.txt expands to files matching *.txt, using this with set we're populating $* with them,
  • if there is no file matching *.txt; it will not expand to anything, it'll stay the same; with test "$*" != '*.txt' we're checking if that's the case,
  • there is one edge case where the only file matching *.txt is a file named *.txt; test -f '*.txt' is for covering that case.

As @Inian suggested, using Bash extension nullglob we could omit the last check. Like:

( shopt -s nullglob; set +f -- *.txt; test "$*" != '' )

However, I think the most advisable approach for this task is to use find ... | read as the condition:

find . ! -name . -prune -name '*.txt' -type f | read

Upvotes: 3

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