[SOLVED] Deleting a string upto first occurrence of right bracket

Issue

I have a file that looks like:

[----------] 7 tests from RouteGenSetup
[ RUN      ] RouteGenSetup.AcceptTATTest
[2021-03-08 22:55:53.937] [info] TimeSlotAssignmentTable::LogTATRow(Add): 1.1 -> 2.1, rounds: LLLLLL, pattern: TR
[2021-03-08 22:55:53.937] [info] TimeSlotAssignmentTable::LogTATRow(Add): 1.1 -> 5.1, rounds: LLLLLL, pattern: TR
[2021-03-08 22:55:53.937] [info] TimeSlotAssignmentTable::LogTATRow(Add): 6.1 -> 7.1, rounds: LLLLLL, pattern: TR
[       OK ] RouteGenSetup.AcceptTATTest (0 ms)
[ RUN      ] RouteGenSetup.BlockLinksTest
[2021-03-08 22:55:53.937] [error] TimeSlotAssignmentTable::LogTATRow(Add): 1.1 -> 2.1, rounds: LLLLLL, pattern: TR
[2021-03-08 22:55:53.938] [error] TimeSlotAssignmentTable::LogTATRow(Add): 1.1 -> 5.1, rounds: LLLLLL, pattern: TR

I want to get rid of the date and time stamp (e.g., [2021-03-08 22:55:53.937]). To do so, I tried using the following sed command:

sed -i '/^\[2021-/s/^.*\]\ //1' output.txt

However, the [info] or [error] bracket to the right of the time stamp also gets deleted:

[----------] 7 tests from RouteGenSetup
[ RUN      ] RouteGenSetup.AcceptTATTest
TimeSlotAssignmentTable::LogTATRow(Add): 1.1 -> 2.1, rounds: LLLLLL, pattern: TR
TimeSlotAssignmentTable::LogTATRow(Add): 1.1 -> 5.1, rounds: LLLLLL, pattern: TR
TimeSlotAssignmentTable::LogTATRow(Add): 6.1 -> 7.1, rounds: LLLLLL, pattern: TR
[       OK ] RouteGenSetup.AcceptTATTest (0 ms)
[ RUN      ] RouteGenSetup.BlockLinksTest
TimeSlotAssignmentTable::LogTATRow(Add): 1.1 -> 2.1, rounds: LLLLLL, pattern: TR
TimeSlotAssignmentTable::LogTATRow(Add): 1.1 -> 5.1, rounds: LLLLLL, pattern: TR

When I try

sed -i '/^\[2021/s/[^\]]*//' output.txt

the first open bracket deletes instead of the first closed bracket:

[----------] 7 tests from RouteGenSetup
[ RUN      ] RouteGenSetup.AcceptTATTest
2021-03-08 22:55:53.937] [info] TimeSlotAssignmentTable::LogTATRow(Add): 1.1 -> 2.1, rounds: LLLLLL, pattern: TR
2021-03-08 22:55:53.937] [info] TimeSlotAssignmentTable::LogTATRow(Add): 1.1 -> 5.1, rounds: LLLLLL, pattern: TR
2021-03-08 22:55:53.937] [info] TimeSlotAssignmentTable::LogTATRow(Add): 6.1 -> 7.1, rounds: LLLLLL, pattern: TR
[       OK ] RouteGenSetup.AcceptTATTest (0 ms)
[ RUN      ] RouteGenSetup.BlockLinksTest
2021-03-08 22:55:53.937] [error] TimeSlotAssignmentTable::LogTATRow(Add): 1.1 -> 2.1, rounds: LLLLLL, pattern: TR
2021-03-08 22:55:53.938] [error] TimeSlotAssignmentTable::LogTATRow(Add): 1.1 -> 5.1, rounds: LLLLLL, pattern: TR

And trying

sed -i '/^\[2021/s/^[^\]]*\]//' output.txt

produces no change. I'm not sure how to fix this. I tried a number of things recommended in similar posts but no luck.

NOTE: This is not a duplicate of sed - regex square brackets detection in Linux because here, the problem is different: only match a substring between the start of string and the first ] + space if the line starts with a certain prefix.

sed replace a word at a line which begins with a specific pattern using does not explain how to get the lines that start with a special character and then match the string from start till the first ] + space.

Solution

You can use

sed -i '/^\[2021-/s/^[^]]*] //' file

Here,

• /^\[2021-/ - finds lines that start with [2021-
• s/^[^]]*] // - matches any zero or more chars other than ] from the start of the string till the first ] and then a space and removes these matches (since the RHS is empty).

Note [^]] is a negated bracket expression that matches any char but ]. Since bracket expressions do not support regex escape sequences, ] needs to be the first char in the bracket expression, you cannot use \] anwhere in a bracket expression.

See an online demo:

s='[----------] 7 tests from RouteGenSetup
[ RUN      ] RouteGenSetup.AcceptTATTest
[2021-03-08 22:55:53.937] [info] TimeSlotAssignmentTable::LogTATRow(Add): 1.1 -> 2.1, rounds: LLLLLL, pattern: TR
[2021-03-08 22:55:53.937] [info] TimeSlotAssignmentTable::LogTATRow(Add): 1.1 -> 5.1, rounds: LLLLLL, pattern: TR
[2021-03-08 22:55:53.937] [info] TimeSlotAssignmentTable::LogTATRow(Add): 6.1 -> 7.1, rounds: LLLLLL, pattern: TR
[       OK ] RouteGenSetup.AcceptTATTest (0 ms)
[ RUN      ] RouteGenSetup.BlockLinksTest
[2021-03-08 22:55:53.937] [error] TimeSlotAssignmentTable::LogTATRow(Add): 1.1 -> 2.1, rounds: LLLLLL, pattern: TR
[2021-03-08 22:55:53.938] [error] TimeSlotAssignmentTable::LogTATRow(Add): 1.1 -> 5.1, rounds: LLLLLL, pattern: TR'
sed '/^\[2021-/s/^[^]]*] //' <<< "$s"

Output:

[----------] 7 tests from RouteGenSetup
[ RUN      ] RouteGenSetup.AcceptTATTest
[info] TimeSlotAssignmentTable::LogTATRow(Add): 1.1 -> 2.1, rounds: LLLLLL, pattern: TR
[info] TimeSlotAssignmentTable::LogTATRow(Add): 1.1 -> 5.1, rounds: LLLLLL, pattern: TR
[info] TimeSlotAssignmentTable::LogTATRow(Add): 6.1 -> 7.1, rounds: LLLLLL, pattern: TR
[       OK ] RouteGenSetup.AcceptTATTest (0 ms)
[ RUN      ] RouteGenSetup.BlockLinksTest
[error] TimeSlotAssignmentTable::LogTATRow(Add): 1.1 -> 2.1, rounds: LLLLLL, pattern: TR
[error] TimeSlotAssignmentTable::LogTATRow(Add): 1.1 -> 5.1, rounds: LLLLLL, pattern: TR

Answered By - Wiktor Stribiżew