problem with sed in a bash script

nexus55 · 05-03-2004, 05:04 AM

Heya guys:

I've got a small problem with the usage of sed..

This works perfectly from the command line:

Code:

echo "ftps://user:pass@some.site.com:port/path" | sed 's/\//\\\//g'

(returns ftps:\/\/user:pass@some.site.com:port\/path as it should)

but when used in a bash script I can't get it to work properly:

if $1 is ftps://user:pass@some.site.com:port/path , then

Code:

R_PATH=`echo "$1" | sed 's/\//\\\//g'`

with that code, $R_PATH should be ftps:\/\/user:pass@some.site.com:port\/path but it doesn't work :(

any suggestions would be appreciated ;)

jschiwal · 05-03-2004, 08:27 AM

from bashref.info:
When the old-style backquote form of substitution is used, backslash
retains its literal meaning except when followed by `$', ``', or `\'.
The first backquote not preceded by a backslash terminates the command
substitution. When using the `$(COMMAND)' form, all characters between
the parentheses make up the command; none are treated specially.

I tried out your example myself using the "$( command )" form of command substitution.

Code:

$ cat test2
#!/bin/bash
export RPATH=$(echo "ftp://ftp.host/user" | sed 's/\//\\\//g')
echo $RPATH
echo
$ . test2
ftp:\/\/ftp.host\/user

$ echo $RPATH
ftp:\/\/ftp.host\/user
$

rkef · 05-03-2004, 08:47 AM

ignore this post, I said something that didn't make sense

nexus55 · 05-03-2004, 12:30 PM

yep the "$( command )" method solved part of my problem indeed, thanks for posting it ;)

another sed-related problem with the same script though, is this:

Code:

#in the below example, $1 is: ftps://user4:pass4@2.2.2.2:34/pppp
  
RPATH_CUR=$(cat $RCF_FILE|grep help.conf\"\;|awk -F \" '{print $2}')
#$RPATH_CUR returns: ftps://user2:pazz5392588@some.2dfre6.com:port/path/help.conf                 
  
RPATH_STRIPPED=${RPATH_CUR%/*}
RPATH_NEW=$(echo $1 | sed 's/\//\\\//g')

sed "s/$RPATH_STRIPPED/$RPATH_NEW/g" < $RCF_FILE > $RCF_FILE.sed

everything works up until the last sed statement, which is where sed returns an error:

Code:

sed: -e expression #1, char 10: Unknown option to 's'

thanks in advance to anyone who can help ;)

jschiwal · 05-03-2004, 07:31 PM

All of these '/'s are confusing me, and apparently sed.

To make things a little less obtuse, use this form instead:

Code:

RPATH_NEW=$(echo $1 | sed 's#/#\\/#g')

sed "s#$RPATH_STRIPPED#$RPATH_NEW#g" $RCF_FILE >$RCF_FILE.sed

After variable expansion, the sed command contains all those forward slashes which you are using as the separation character. Now you'd have a problem if '#'s are used.

nexus55 · 05-03-2004, 08:43 PM

excellent! that worked!

I didn't know different separation characters could be used with sed, but that has fixed the remaining problems..

thank you again jschiwal!

FinalFantasy · 05-03-2004, 09:40 PM

: (colon) and # (hash) are another two seperators avaiable besides / (forword slash).