How to avoid next line in BASH script

Question

I am trying to read table names and index names from two different text files and then building the sql files which can be used to do the de-fragmentation and index re-building. It is working fine as of now but generated sql file contains next line after table/index name. PFB script and sample outputs.

BASH Script:

#!/bin/bash

export logfile=/tmp/logfile.log
export tablenamesfile=/tmp/tablenames.txt
export tabledefragfile=/tmp/tabledefrag.sql
export indexnamesfile=/tmp/indexnames.txt
export indexrebuildfile=/tmp/indexrebuild.sql

while read line; do echo "alter table $line enable row movement;" >> $tabledefragfile; echo "alter table $line shrink space;" >> $tabledefragfile; echo "alter table $line disable row movement;" >> $tabledefragfile; done < $tablenamesfile
echo "Please check sql file - $(readlink -f $tabledefragfile)"

while read line; do echo "alter index $line rebuild parameters('tablespace=TBS_3');" >> $indexrebuildfile; done < $indexnamesfile
echo "Please check sql file - $(readlink -f $indexrebuildfile)"

exit

Current output in tabledefrag.sql

alter table APA_DS_DATASTORE
 enable row movement;
alter table APA_DS_DATASTORE
 shrink space;
alter table APA_DS_DATASTORE
 disable row movement;

Current output in indexrebuild.sql

alter index APA_DS_DATASTORE_PK
 rebuild parameters('tablespace=TBS_3');
alter index APA_FS_DEFAULT_FSENTRY_IDX
 rebuild parameters('tablespace=TBS_3');
alter index APA_FS_DEFAULT_FSENTRY_IDX
 rebuild parameters('tablespace=TBS_3');

Expected output:

alter index APA_DS_DATASTORE_PK rebuild parameters('tablespace=TBS_3');
alter index APA_FS_DEFAULT_FSENTRY_IDX rebuild parameters('tablespace=TBS_3');
alter index APA_FS_DEFAULT_FSENTRY_IDX rebuild parameters('tablespace=TBS_3');

@alecxs input is taken from two different text files which contain table/index names like below. Each table/index name is on new line... APA_DS_DATASTORE_PK APA_FS_DEFAULT_FSENTRY_IDX — Ranjeet
– Ranjeet, Commented Jul 13, 2020 at 12:51
hm.. right, understand the issue now. don't know if that is expected but seems read does save \n as last byte into $line, so the proper way would be to tell read not to do that (but i don't know how). as workaround you can echo without quotes, or remove the last byte (in general ${line%?} or explicit ${line//$'\n'}) — alecxs
– alecxs, Commented Jul 13, 2020 at 13:45
you can edit your question and add the output of printf "%s" "$line" | hexdump -C for debugging purposes — alecxs
– alecxs, Commented Jul 13, 2020 at 13:49
@alecxs issue is resolved by putting while IFS=$' \t\n\r' read -r line. Thank you for your time and help. — Ranjeet
– Ranjeet, Commented Jul 13, 2020 at 13:56

Lorccan · Accepted Answer · 2020-07-13 13:05:59Z

2

echo has a newline by default. You should use printf instead.

You'll also need to avoid the newline coming from the file: while IFS=$' \t\n\r' read -r LINE

edited Jul 13, 2020 at 13:05

answered Jul 13, 2020 at 12:11

Lorccan

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4 Comments

Ranjeet Over a year ago

printf didn't resolve the issue. My issue is that there is new line after I print table name using $line in echo. Remaining part of the statement for e.g. 'enable row movement;' should be printed in the same line.

Lorccan Over a year ago

while IFS=$' \t\n\r' read -r line should fix it. I'll edit my answer.

Ranjeet Over a year ago

I just added while IFS=$' \t\n\r' read -r line. 'echo' remains as it is. So, maybe you can remove the suggestion to use 'printf' from answer. Now, I am getting the desired output. Thank you for the help.

Lorccan Over a year ago

You would be well advised to use printf in place of echo to avoid issues in future - even of its not the cause of this problem.

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