[SOLVED] Inserting variable after pattern using sed

Issue

Hi I try to use Sed in a Bash script and I'm facing a problem. (I'm new to both of them)

I'm trying to insert $log after the flag <!-- Beginning git log -->.

#!/bin/bash
log=`git log -1 --stat --date=short --pretty=format:'[ %cd | %an | %s ]'`
sed "/<!-- Beginning git log -->/a $log" ~/opt/prime.dropbox/commit.md

So in commit.md I would have :

some text
<!-- Beginning git log -->
git log output
some text

I have tried all possible single/double quotes tricks,.. or maybe only all the wrong ones.

This is the error I get most of the time.

sed: -e expression #1, char 102: unknown command: `f'

I know there should be an easier way with awk, but I'm so close. ^^

Maybe are the Html chars <!-- --> blocking or something ?

Thx

Solution

sed is an excellent tool for simple substitutions on a single line, but for anything else, just use awk:

awk -v gitlog="$log" '{print} /<!-- Beginning git log -->/{print gitlog}' ~/opt/prime.dropbox/commit.md

To run a command in shell and safely over-write the original file with that commands output:

the_command orig_file > /usr/tmp/tmp$$ && mv /usr/tmp/tmp$$ orig_file

In this case:

awk -v gitlog="$log" '{print} /<!-- Beginning git log -->/{print gitlog}' ~/opt/prime.dropbox/commit.md > /usr/tmp/tmp$$ &&
mv /usr/tmp/tmp$$ ~/opt/prime.dropbox/commit.md

The temporary file can be in your working directory or in your $HOME or in /usr/tmp or wherever you want and can be named whatever you want.

Answered By - Ed Morton

Answer Checked By - Willingham (WPSolving Volunteer)