Hello, GNU grep bug reporting team, in the section "2.1.7 Other Options" of the "grep" "info" documentation (for example in <https://www.gnu.org/software/grep/manual/html_node/Other-Options.html>), the hint about the usage of the "--" option delimiter is wrong: It won't work, if the pattern "PAT" happens to start with a "-". And if the environment variable "POSIXLY_CORRECT" is set, it won't even work with any pattern (except the pattern "--").
The following example may show it:
How to reproduce: In an empty directory, run the following
commands:
printf '%s\n' -1 +1 > -file1 &&
printf '%s\n' -2 +2 > file2 &&
grep '-[[:digit:]]' -- -file1 file2
Received output:
grep: invalid option -- '['
Usage: grep [OPTION]... PATTERN [FILE]...
Try `grep --help' for more information.
Expected output: According to the manual, the output should be
-file1:-1
file2:-2
=> The hint in the documentation is wrong: Rather than
‘--’
Delimit the option list. Later arguments, if any, are
treated as operands even if they begin with ‘-’. For
- example, ‘grep PAT -- -file1 file2’ searches for the
pattern PAT in the files named ‘-file1’ and ‘file2’.
it should say:
‘--’
Delimit the option list. Later arguments, if any, are
treated as operands even if they begin with ‘-’. For
+ example, ‘grep -- PAT -file1 file2’ searches for the
pattern PAT in the files named ‘-file1’ and ‘file2’.
(the differing lines are marked in the first position with "-"
resp. "+").
Working example:
printf '%s\n' -1 +1 > -file1 &&
printf '%s\n' -2 +2 > file2 &&
grep -- '-[[:digit:]]' -file1 file2
Received output:
-file1:-1
file2:-2
Explanation: As the pattern PAT shall be the first non-option
argument given to "grep", the option list delimiter "--", when
placed before the pattern in "grep"s invocation arguments list,
prevents the pattern from being misinterpreted as an option
(regardless of the POSIXLY_CORRECT environment variable being set
or unset).
Kind regards
Helmut Waitzmann
pgphLbtVKDmMd.pgp
Description: PGP signature
