sed, foward slash in quotes

Question

I'm trying to do something in bash with sed that is proving to be extremely difficult.

I have a bash script that takes as its first argument a date.

The code want to change a line in a text file to include the passed date. Here's the code

#!/bin/bash

cq_fname="%let outputfile="/user/cq_"$1".csv";"

sed "29s/.*/\"$ct_fname\"/" file1.sas > file2.sas

This script fails on the third line, I get something about a garbled command. Does anybody know a clever way to get this to work? How can I get a forward slash in quotes in sed?

Answer 1

You can use any character in place of the /, so just pick one that is not in $ct_fname:

sed "29s|.*|\"$ct_fname\"|" file1.sas > file2.sas

Answer 2

The syntax highlighting here should be a good indicator of what your problem is -- you've got several strings smashed together with content that isn't in the strings. Try replacing this:

cq_fname="%let outputfile="/user/cq_"$1".csv";"

with this:

cq_fname="%let outputfile=\"/user/cq_$1.csv\";"

I escaped the " inside the string with \ characters and removed the " characters that felt like they probably don't exist in the filename.

Alok suggests using a different character for the replacement command -- that's necessary.

Also, you need to use the same variable name in both the assignment and the string. (D'oh!)

The final script is:

#!/bin/bash
cq_fname="%let outputfile=\"/user/cq_$1.csv\";"
sed "29s|.*|$cq_fname|" file1.sas > file2.sas

I found the mis-matched variable names by adding set -x to the top of the script; it showed the execution output of the script along the way.

Broken:

$ ./replace 
+ cq_fname='%let outputfile="/user/cq_.csv";'
+ sed '29s|.*||' file1.sas

Fixed:

$ ./replace 
+ cq_fname='%let outputfile="/user/cq_.csv";'
+ sed '29s|.*|%let outputfile="/user/cq_.csv";|' file1.sas

set -x is a superb little debugging tool, when you need it.

Answer 3

On every other set of quotes, use ' (single quote) instead of " (double quote).

Answer 4

This might work for you:

cq_fname='%let outputfile="/user/cq_.csv";'
sed '29c\'"$cq_fname" file1.sas > file2.sas