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Remove comments from files

Terminal - Remove comments from files
sed -e '/^#/d' -e 's/#.*$//' in
2012-01-25 15:05:57
User: agambier
Functions: sed
Remove comments from files

Use sed to remove comments from a file.

In this example the comments begin with #.

The command '/^#/d' remove line starting with #.

The command 's/#.*$//' remove comments at end of lines.


There are 7 alternatives - vote for the best!

Terminal - Alternatives
sed -i -e '/^#[^!].*/d' -e 's/\(.*[^!]\)#.*[^}]/\1/' <filename>
2012-01-31 02:45:56
User: jlaunay
Functions: sed

as suggest in frans coment :

'/^#[^!].*/d' -> remove if line begin with # except shebang #!/bin/bash

's/\(.*[^!]\)#.*[^}]/\1/' -> remove inline comments except shebang and ${variable#}

sed -re '/^#/d ; s/#.*$//'
2012-02-01 20:39:23
User: Zulu
Functions: sed
Tags: sed

Delete all comments (#) on text :

It deletes the entire comment line and remove comments form end of others.

Know a better way?

If you can do better, submit your command here.

What others think

Just take care when the '#' is used for any other purpose than commenting !

- in a string

- in bash substitution like ${variable#}

Comment by frans 168 weeks and 3 days ago

A decent effort but its flawed as Franz pointed out above.. as well as his examples it also removes shebang lines.

Removing comments at end of lines is a tricky problem no doubt.

Comment by zlemini 167 weeks and 5 days ago


But I did not understand the syntax of this command, but the line below is also an alternative to remove the comments "#" of the specified files.

sed-i-r 's /^#// g' testes.txt

The command you provided is just a filter on the file and print only after the same lines that do not have comments, or if the case of a configuration file, you can print only the rows that do not have the "#".

I hope to have collaborated with everyone!


Julio C. S. Ferraz

Comment by julioferraz 167 weeks and 5 days ago

frans: you're right, but I used this command to remove comments from a configuration file not a script file.

To protect shebang you can use the following command:

sed -e 's/^#!/__SHEBANG__/' -e '/^#/d' -e 's/#.*$//' -e 's/^__SHEBANG__/#!/'

The shebang is first shebang '#!' replaced by __SHEBANG__ so the line won't be removed then comments are removed and at last __SHEBANG__ is replaced by the real shebang '#!'.

I guess there's a another cleaner way to perform it.

But it doesn't fix the case showed by frans.

Comment by agambier 167 weeks and 5 days ago

Your point of view

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