How can I add a line to a file in a shell script

Question

I want to add a row of headers to an existing CSV file  editing in place  How can I do this   echo  one  two  three   gt  testfile csv   and I want to end up with  column1  column2  column3 one      two      three   Changing the initial CSV output is out of my hands   Any standard command will do  The important thing is the file is edited in place  and the line is inserted at the beginning of the file

User · Answer

sed is line based  so I m not sure why you want to do this with sed  The paradigm is more processing one line at a time  you could also programatically find the   of fields in the CSV and generate your header line with awk  Why not just   echo  c1  c2         gt  gt  file cat testfile csv  gt  gt  file

User · Answer

Add a given line at the beginning of a file in two commands   cat  lt  echo  blablabla   input file txt  gt  tmp file txt mv tmp file txt input file txt

User · Answer

sed is line based  so I m not sure why you want to do this with sed  The paradigm is more processing one line at a time  you could also programatically find the   of fields in the CSV and generate your header line with awk  Why not just   echo  c1  c2         gt  gt  file cat testfile csv  gt  gt  file

User · Answer

sed is line based  so I m not sure why you want to do this with sed  The paradigm is more processing one line at a time  you could also programatically find the   of fields in the CSV and generate your header line with awk  Why not just   echo  c1  c2         gt  gt  file cat testfile csv  gt  gt  file

User · Answer

To answer your original question  here s how you do it with sed   sed -i  1icolumn1  column2  column3  testfile csv   The  1i  command tells sed to go to line 1 and insert the text there   The -i option causes the file to be edited  in place  and can also take an optional argument to create a backup file  for example  sed -i   1icolumn1  column2  column3  testfile csv   would keep the original file in  testfile csv

User · Answer

To answer your original question  here s how you do it with sed   sed -i  1icolumn1  column2  column3  testfile csv   The  1i  command tells sed to go to line 1 and insert the text there   The -i option causes the file to be edited  in place  and can also take an optional argument to create a backup file  for example  sed -i   1icolumn1  column2  column3  testfile csv   would keep the original file in  testfile csv

User · Answer

This adds custom text at the beginning of your file   echo  your custom escaped content   gt  temp file csv cat testfile csv  gt  gt  temp file csv mv temp file csv testfile csv

User · Answer

Use perl -i  with a command that replaces the beginning of line 1 with what you want to insert  the  bk will have the effect that your original file is backed up    perl -i bk -pe  s   column1  column2  column3 n  if     1   testfile csv

User · Answer

This doesn t use sed  but using    will append to a file   For example   echo  one  two  three   gt  gt  testfile csv   Edit  To prepend to a file  try something like this   echo  text  cat - yourfile  gt   tmp out  amp  amp  mv  tmp out yourfile   I found this through a quick Google search

User · Answer

As far as I understand  you want to prepend column1  column2  column3 to your existing one  two  three   I would use ed in place of sed  since sed write on the standard output and not in the file   The command   printf  0a ncolumn1  column2  column3 n  nw n    ed testfile csv   should do the work   perl -i is worth taking a look as well

User · Answer

This adds custom text at the beginning of your file   echo  your custom escaped content   gt  temp file csv cat testfile csv  gt  gt  temp file csv mv temp file csv testfile csv

User · Answer

As far as I understand  you want to prepend column1  column2  column3 to your existing one  two  three   I would use ed in place of sed  since sed write on the standard output and not in the file   The command   printf  0a ncolumn1  column2  column3 n  nw n    ed testfile csv   should do the work   perl -i is worth taking a look as well

User · Answer

This adds custom text at the beginning of your file   echo  your custom escaped content   gt  temp file csv cat testfile csv  gt  gt  temp file csv mv temp file csv testfile csv

User · Answer

To answer your original question  here s how you do it with sed   sed -i  1icolumn1  column2  column3  testfile csv   The  1i  command tells sed to go to line 1 and insert the text there   The -i option causes the file to be edited  in place  and can also take an optional argument to create a backup file  for example  sed -i   1icolumn1  column2  column3  testfile csv   would keep the original file in  testfile csv

User · Answer

As far as I understand  you want to prepend column1  column2  column3 to your existing one  two  three   I would use ed in place of sed  since sed write on the standard output and not in the file   The command   printf  0a ncolumn1  column2  column3 n  nw n    ed testfile csv   should do the work   perl -i is worth taking a look as well

User · Answer

This adds custom text at the beginning of your file   echo  your custom escaped content   gt  temp file csv cat testfile csv  gt  gt  temp file csv mv temp file csv testfile csv

User · Answer

This doesn t use sed  but using    will append to a file   For example   echo  one  two  three   gt  gt  testfile csv   Edit  To prepend to a file  try something like this   echo  text  cat - yourfile  gt   tmp out  amp  amp  mv  tmp out yourfile   I found this through a quick Google search

User · Answer

Use perl -i  with a command that replaces the beginning of line 1 with what you want to insert  the  bk will have the effect that your original file is backed up    perl -i bk -pe  s   column1  column2  column3 n  if     1   testfile csv

User · Answer

Use perl -i  with a command that replaces the beginning of line 1 with what you want to insert  the  bk will have the effect that your original file is backed up    perl -i bk -pe  s   column1  column2  column3 n  if     1   testfile csv

User · Answer

To answer your original question  here s how you do it with sed   sed -i  1icolumn1  column2  column3  testfile csv   The  1i  command tells sed to go to line 1 and insert the text there   The -i option causes the file to be edited  in place  and can also take an optional argument to create a backup file  for example  sed -i   1icolumn1  column2  column3  testfile csv   would keep the original file in  testfile csv

User · Answer

sed is line based  so I m not sure why you want to do this with sed  The paradigm is more processing one line at a time  you could also programatically find the   of fields in the CSV and generate your header line with awk  Why not just   echo  c1  c2         gt  gt  file cat testfile csv  gt  gt  file

User · Answer

This doesn t use sed  but using    will append to a file   For example   echo  one  two  three   gt  gt  testfile csv   Edit  To prepend to a file  try something like this   echo  text  cat - yourfile  gt   tmp out  amp  amp  mv  tmp out yourfile   I found this through a quick Google search

User · Answer

As far as I understand  you want to prepend column1  column2  column3 to your existing one  two  three   I would use ed in place of sed  since sed write on the standard output and not in the file   The command   printf  0a ncolumn1  column2  column3 n  nw n    ed testfile csv   should do the work   perl -i is worth taking a look as well

User · Answer

This doesn t use sed  but using    will append to a file   For example   echo  one  two  three   gt  gt  testfile csv   Edit  To prepend to a file  try something like this   echo  text  cat - yourfile  gt   tmp out  amp  amp  mv  tmp out yourfile   I found this through a quick Google search

User · Answer

Use perl -i  with a command that replaces the beginning of line 1 with what you want to insert  the  bk will have the effect that your original file is backed up    perl -i bk -pe  s   column1  column2  column3 n  if     1   testfile csv

User · Answer

Add a given line at the beginning of a file in two commands   cat  lt  echo  blablabla   input file txt  gt  tmp file txt mv tmp file txt input file txt

[linux] How can I add a line to a file in a shell script?

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