Remove commas between patterns

Question

I am trying to replace all commas with a space between ";" and "[" in my text file using sed. An example line is: K01810,GPI,,pgi;,glucose-6-phosphate,isomerase,[EC:5.3.1.9] where my ideal output is K01810,GPI,,pgi; glucose-6-phosphate isomerase [EC:5.3.1.9].

I have tried sed 's/;\(.*\)\[/;\1[/g' myfile.txt > newfile but that didn't change anything.

myfile.txt:

09100,Metabolism
09101,Carbohydrate,metabolism
00010,Glycolysis,/,Gluconeogenesis,[PATH:ko00010]
K00844,HK;,hexokinase,[EC:2.7.1.1]
K12407,GCK;,glucokinase,[EC:2.7.1.2]
K00845,glk;,glucokinase,[EC:2.7.1.2]
K25026,glk;,glucokinase,[EC:2.7.1.2]
K01810,GPI,,pgi;,glucose-6-phosphate,isomerase,[EC:5.3.1.9]
K06859,pgi1;,glucose-6-phosphate,isomerase,,archaeal,[EC:5.3.1.9]
K13810,tal-pgi;,transaldolase,/,glucose-6-phosphate,isomerase,[EC:2.2.1.2,5.3.1.9]
K15916,pgi-pmi;,glucose/mannose-6-phosphate,isomerase,[EC:5.3.1.9,5.3.1.8]
K24182,PFK9;,6-phosphofructokinase,[EC:2.7.1.11]
K00850,pfkA,,PFK;,6-phosphofructokinase,1,[EC:2.7.1.11]
K16370,pfkB;,6-phosphofructokinase,2,[EC:2.7.1.11]

Answer 1

sed '
    # skip lines that do not match
    /^\(.*\)\(;.*\[\)\(.*\)$/ ! b

    # save a copy of original line
    h

    # extract prefix/suffix
    s//\1\n\3/

    # save them, restore original line
    x

    # extract part to change
    s//\2/

    # do the substitution
    y/,/ /

    # append prefix/suffix
    G

    # rearrange
    s/^\([^\n]*\)\n\([^\n]*\)\n/\2\1/
    
' myfile.txt >newfile

---

Note: For portability, escaped literal newline is required in replacement (some versions of sed treat \n as just n):

    # ...

    # extract prefix/suffix
    s//\1\
\3/

    # ...