Shell Programming and Scripting

Hi

I have to remove in a file in first column whatever is written in brackets with brackets [ xyz]

so one file

Code:

hgfd[xtd]   123
gfhdj[dfg]  483
jdgfdg[urtr]  34738

the output shuld be

Code:

hgfd    123
gfhdj   483
jdgfdg  34738

Code:

echo 'hgfd[xtd]   123' | sed 's/\[[^]]*\]//1'

use sed:

Code:

sed 's/\[.*\]//' filename

Be careful with something like this. While it didn't appear in the small sample posted, if the input line contained something like

Code:

foo[bar] some other text[3]

The sed here would leave only 'foo' in the record. Remember, regex is a greedy match and \[.*\] will match from the left most bracket through the last bracket on the line. The expression that vgersh99 posted does not fall victim to this as there is cleverness coded that prevents the match from extending past the first closing bracket.

Would you please explain more about this? I have added some blank for read convenience.

Code:

sed 's  /   \[  [^]]  *   \]   //1  '

---------- Post updated at 02:31 AM ---------- Previous update was at 02:27 AM ----------

And by the way, if I want to delete the bracket pair with sed, leaving the content within the bracket.
How?
Thank you in advance.

[^]]* that means all characters but "]" zero or more times.
\[[^]]*\] on "[brackettext1] some other text [brackettext2] some different text"
will find "[brackettext1]"
but \[.*\]
will find "[brackettext1] some other text [brackettext2]"

And to keep the bracket text:

Code:

 echo 'hgfd[xtd]   123' | sed -E 's/\[([^]]*)\]/\1/'

Outside of a bracket expression, ] does not need to be escaped. It is not special.

In \[[^]]*\] and \[.*\], according to POSIX, \] is an undefined sequence. Most regular expression implementations will throw away the backslash, but they aren't required to. It would be compliant to abort with a syntax error.

Within a bracket expression, where backslash and other special characters lose their special meaning, \] simply means a literal backslash is the final character in the bracket expression.

Regards,
Alister