tcsh script, replace word in file

true_atlantis · 02-16-2006, 04:13 PM

ok, i am trying to write a script in tcsh that replaces like this

rep1 file word1 word2 [word1 word2 ...]

where it will replace word1 with word2 in the file named file.

i am using sed, but for some reason, it will not actually do any replacing... anyone see why? or have an easier way to do this?

Code:

#!/bin/tcsh

#check number of arguments
if ( $#argv < 3 ) then
   echo Usage: rep1 file string1 string2 [string1 string2 ...]
   echo Usage: where string1 is replaced by string2 in file
   echo Warning: If there is an odd number of strings, the last will be cut off!
else
    #argv[1] = file

    #does the file exist?
    if( -e $argv[1] ) then
        #check if backup file exists
        if ( -e $argv[1]_backup) then
            echo "ERROR: backup file already exists ($argv[1]_backup)"
            exit
        endif

        #create backup
        #cp $argv[1] $argv[1]_backup

        @ ptr = 2
        @ ptr2 = 3
        # $argv[$ptr] = word to search for
        # $argv[$ptr + 1] = word to replace with
        while ( $ptr < $#argv )
            echo "          sed -e 's/$argv[$ptr]/$argv[$ptr2]/g' $argv[1] "
            sed -e 's/$argv[$ptr]/$argv[$ptr2]/g' $argv[1]
            @ ptr += 2
            @ ptr2 += 2
        end

    else
        #file does not exist
        echo "ERROR: File does not exist ($argv[1])"
        exit
    endif
endif

bigearsbilly · 02-16-2006, 04:24 PM

Code:

perl -pi.bak -e 's/THIS/THAT/g' -e 's/WHO/WHERE/g' file ...

true_atlantis · 02-16-2006, 05:44 PM

i get the same problem if i insert that instead of the 'sed' command. it doesnt do anything to the file. but if i do either of those commands from a shell they will work..

gilead · 02-16-2006, 06:38 PM

I don't have a PC here to test it on, but it could be the variables inside the single quotes aren't being expanded. Can you try double quotes in the sed command?

true_atlantis · 02-17-2006, 03:03 AM

i get..

sed -e 's/1/2/g' aaa: Command not found.

gilead · 02-17-2006, 03:09 AM

So it's resolving:

Code:

sed -e 's/$argv[$ptr]/$argv[$ptr2]/g' $argv[1]

As

Code:

sed -e 's/1/2/g' aaa

And not finding the sed command. That's odd - have you tried it with the full path to sed?

bigearsbilly · 02-17-2006, 04:32 AM

well, the variables won't get expanded because they are in single quotes.
's/$argv[$ptr]/$argv[$ptr2]/g'
use double quotes.

Code:

> set x=`date`
> echo $x
Fri Feb 17 10:30:58 GMT 2006
> echo '$x'
$x

google:"c shell considered harmful"

repeat ...

Code:

perl -pi.bak -e 's/THIS/THAT/g' -e 's/WHO/WHERE/g' file ...

true_atlantis · 02-17-2006, 12:25 PM

its resolving the arguments all right, those are what i entered in the command line... its just not executing the command... if i try with perl, i get

perl -pi.bak 's/1/2/g' aaa: Command not found.

is there a specific way you have to execute a command in tcsh?

the weird thing is, it will create the backupfile, if i try it without quotes, but it will just not replace the words...

if this is not going to work, how do i read a file in tcsh? word for word?

gilead · 02-17-2006, 01:02 PM

It's running on my PC under the following setup. I have a file called aaa which contains several outputs of the date command. I have a script which is basically the one you posted earlier but with double quotes instead of single quotes for the sed command:

Code:

#!/bin/tcsh
#

if ( $#argv < 3 ) then
   echo Usage: rep1 file string1 string2 [string1 string2 ...]
   echo Usage: where string1 is replaced by string2 in file
   echo Warning: If there is an odd number of strings, the last will be cut off!
else
    #argv[1] = file

    #does the file exist?
    if( -e $argv[1] ) then
        #check if backup file exists
        if ( -e $argv[1]_backup) then
            echo "ERROR: backup file already exists ($argv[1]_backup)"
            exit
        endif

        #create backup
        #cp $argv[1] $argv[1]_backup

        @ ptr = 2
        @ ptr2 = 3
        # $argv[$ptr] = word to search for
        # $argv[$ptr + 1] = word to replace with
        while ( $ptr < $#argv )
            echo "          sed -e s/$argv[$ptr]/$argv[$ptr2]/g $argv[1] "
            sed -e "s/$argv[$ptr]/$argv[$ptr2]/g" $argv[1]
            @ ptr += 2
            @ ptr2 += 2
        end

    else
        #file does not exist
        echo "ERROR: File does not exist ($argv[1])"
        exit
    endif
endif

When I enter a tcsh shell (just in case you were using one as well as your script) and check the contents of aaa and then run the script, it does the substitution:

Code:

$ /bin/tcsh
> cat ./aaa
Sat Feb 18 04:40:46 EST 2006
Sat Feb 18 04:40:49 EST 2006
Sat Feb 18 04:40:49 EST 2006
Sat Feb 18 04:40:50 EST 2006
Sat Feb 18 04:40:50 EST 2006
Sat Feb 18 04:40:51 EST 2006
> ./runme aaa EST ABC
          sed -e s/EST/ABC/g aaa
Sat Feb 18 04:40:46 ABC 2006
Sat Feb 18 04:40:49 ABC 2006
Sat Feb 18 04:40:49 ABC 2006
Sat Feb 18 04:40:50 ABC 2006
Sat Feb 18 04:40:50 ABC 2006
Sat Feb 18 04:40:51 ABC 2006
> exit

If it were a disk space problem you should get an IO error, if it were the permissions of the script, you should get permission denied. If I modify the name of the sed command to something else, I get Command not found.

Can you try it again with the full path to sed as the command (e.g. /bin/sed or /usr/bin/sed)?

true_atlantis · 02-17-2006, 01:21 PM

the problem is that tcsh does not interperate anything in single quotes... the problem before was i was putting the whole command in double quotes (idiot)

gilead · 02-17-2006, 01:24 PM

Well, if it's working now - that's a good thing