I have one question in shell script for escape "\" with command substitution "` `". I post there to seek help to understand how it works.
My original one piece of code in script like this: This piece of code in whole script is working without errors
Code:
chk_mode=`sqlplus -s /nolog<<EOF
connect / as sysdba
set pagesize 0 feedback off heading off
select open_mode from v\\\$database;
EOF`
Usually if I want to escape $ sign from v$database, I should use "v\$database". Why is this piece of code using 3 backslash as v\\\$database? Is this because the backslash is in command substitution(backtick)? I tested in command line: only v\$database works, v\\\$database is not working. My Unix server is solaris 11.3 and SHELL is bash.
Please help me to understand why using 3 backslashes as escape. Thanks for your advice.
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"Is there any substituation of last command or script syntax which can be used as a user. As far I know the "last" command is being used to display information about previous logins. A member of adm group or the user adm can execute it only.
Thanks in advance for your usual help.
Ghazi (6 Replies)
Hi,
What is the actual difference between these two? Why the following code works for process substitution and fails for command substitution?
while IFS= read -r line; do echo $line; done < <(cat file)executes successfully and display the contents of the file
But,
while IFS='\n' read -r... (3 Replies)
The following statement does work. But the second command does not work as expected.
ssh root@123.123.123.123 \\"mysqldump -h localhost -u root -pPassWord dbName -d | gzip -cf\\" | gunzip -c > database1.sql
ssh root@123.123.123.123 \\"mysqlbinlog /var/log/mysql/mysql-bin.*... (0 Replies)
I know this script is crummy, but I was just messing around.. how do I get sed's insert command to allow variable expansion to show the filename?
#!/bin/bash
filename=`echo $0`
/usr/bin/sed '/#include/ {
i\
the filename is `$filename`
}' $1
exit 0 (8 Replies)
I have a file that is a log file for web traffic. I would like to convert the timestamp in it to unix time or epoch time.
I am using the date command in conjunction with awk to try to do this. Just
myfile:
28/Aug/1995:00:00:38 1 /pub/atomicbk/catalog/home.gif 813
28/Aug/1995:00:00:38 1... (3 Replies)
Hey, guys!
Trying to research this is such a pain since the read command itself is a common word. Try searching "unix OR linux read command examples" or using the command substitution keyword. :eek:
So, I wanted to use a command statement similar to the following.
This is kinda taken... (2 Replies)
Hi guys, I'm looking for some thoughts on this. I'm trying to do a clean 1 liner to substitute some values. What I have:
sed 's/Personid=.*/Personid=xxxxxx/' $tmpFileOut
sed 's/Person:.*/Person:xxxxxx/' $tmpFileOut
sed 's/PersonID:.*/PersonID: xxxxxx/' $tmpFileOut
Obviously that's a bit... (1 Reply)
mv myFile.txt myFile.txt.bak
sed s/foo/bar/g myFile.txt.bak > myFile.txt
Turn the two-line version, above, of the substitution commands into a shell script, subst1 taking three parameters:
the string to be replaced
the string with which to replace it
the name of the file in which to make the... (1 Reply)
This is a bit off the wall, but I often need to run scripts where there are argument values that contain special characters.
For example,
$ ./process.exe -t M -N -o temp.mol.s -i ../molfiles/N,N\',N\'\'-trimethylbis\(hexamethylene\)triamine.mol && sfile_space_to_tab.sh temp.mol.s temp.s
It... (1 Reply)
Oracle Linux 5.6, 64-bit
Given the following snippet
wrkvar=`sqlplus -s / as sysdba <<EOF
set echo off feedback off head off trimsp on
select count(*) from v\$parameter
where name in ('db_file_name_convert','log_file_name_convert')
and value is not null;
EOF`
echo wrkvar=$wrkvarProduces... (2 Replies)
Discussion started by: edstevens
2 Replies
LEARN ABOUT SUNOS
exit
exit(1) User Commands exit(1)NAME
exit, return, goto - shell built-in functions to enable the execution of the shell to advance beyond its sequence of steps
SYNOPSIS
sh
exit [n]
return [n]
csh
exit [ ( expr )]
goto label
ksh
*exit [n]
*return [n]
DESCRIPTION
sh
exit will cause the calling shell or shell script to exit with the exit status specified by n. If n is omitted the exit status is that of
the last command executed (an EOF will also cause the shell to exit.)
return causes a function to exit with the return value specified by n. If n is omitted, the return status is that of the last command exe-
cuted.
csh
exit will cause the calling shell or shell script to exit, either with the value of the status variable or with the value specified by the
expression expr.
The goto built-in uses a specified label as a search string amongst commands. The shell rewinds its input as much as possible and searches
for a line of the form label: possibly preceded by space or tab characters. Execution continues after the indicated line. It is an error to
jump to a label that occurs between a while or for built-in command and its corresponding end.
ksh
exit will cause the calling shell or shell script to exit with the exit status specified by n. The value will be the least significant 8
bits of the specified status. If n is omitted then the exit status is that of the last command executed. When exit occurs when executing
a trap, the last command refers to the command that executed before the trap was invoked. An end-of-file will also cause the shell to exit
except for a shell which has the ignoreeof option (See set below) turned on.
return causes a shell function or '.' script to return to the invoking script with the return status specified by n. The value will be the
least significant 8 bits of the specified status. If n is omitted then the return status is that of the last command executed. If return
is invoked while not in a function or a '.' script, then it is the same as an exit.
On this man page, ksh(1) commands that are preceded by one or two * (asterisks) are treated specially in the following ways:
1. Variable assignment lists preceding the command remain in effect when the command completes.
2. I/O redirections are processed after variable assignments.
3. Errors cause a script that contains them to abort.
4. Words, following a command preceded by ** that are in the format of a variable assignment, are expanded with the same rules as a vari-
able assignment. This means that tilde substitution is performed after the = sign and word splitting and file name generation are not
performed.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|Availability |SUNWcsu |
+-----------------------------+-----------------------------+
SEE ALSO break(1), csh(1), ksh(1), sh(1), attributes(5)SunOS 5.10 15 Apr 1994 exit(1)
10-25-2017
