06-19-2006
Shells let you do stuff like this:
command1 ; command2
and that is exactly what you want to prevent. But what about:
command1 && command2
command || command2
One of those would work, depending on the exit code from your shell script. This is probably legal too:
command1 & command2
And there are other variants. The best way to protect yourself is to get rid of system() and instead just fork() and exec().
10 More Discussions You Might Find Interesting
1. Shell Programming and Scripting
Hi
how to check input is "empty" and "numeric" in ksh?
e.g:
./myscript.ksh k
output show: invalid number input
./myscript.ksh
output show: no input
./myscript.ksh 10
output show: input is numeric (6 Replies)
Discussion started by: geoffry
6 Replies
2. Shell Programming and Scripting
input string="3MMTQSZ348GGMZRQWMJM4SD6M"
output string="3MMTQ-SZ348-GGMZR-QWMJM-4SD6M"
using linux shell script (4 Replies)
Discussion started by: pankajd
4 Replies
3. Shell Programming and Scripting
Hi,
I have line in input file as below:
3G_CENTRAL;INDONESIA_(M)_TELKOMSEL;SPECIAL_WORLD_GRP_7_FA_2_TELKOMSEL
My expected output for line in the file must be :
"1-Radon1-cMOC_deg"|"LDIndex"|"3G_CENTRAL|INDONESIA_(M)_TELKOMSEL"|LAST|"SPECIAL_WORLD_GRP_7_FA_2_TELKOMSEL"
Can someone... (7 Replies)
Discussion started by: shis100
7 Replies
4. Shell Programming and Scripting
Hello everyone
Sorry I have to add another sed question. I am searching a log file and need only the first 2 occurances of text which comes after (note the space) "string " and before a ",". I have tried
sed -n 's/.*string \(*\),.*/\1/p' filewith some, but limited success. This gives out all... (10 Replies)
Discussion started by: haggismn
10 Replies
5. Shell Programming and Scripting
logs:
"/home/abc/public_html/index.php"
"/home/abc/public_html/index.php"
"/home/xyz/public_html/index.php"
"/home/xyz/public_html/index.php"
"/home/xyz/public_html/index.php"
how to use "cut" or "awk" or "sed" to get the following result:
abc
abc
xyz
xyz
xyz (8 Replies)
Discussion started by: timmywong
8 Replies
6. Shell Programming and Scripting
I came across and unexpected behavior with redirections in tcsh. I know, csh is not best for redirections, but I'd like to understand what is happening here.
I have following script (called out_to_streams.csh):
#!/bin/tcsh -f
echo Redirected to STDOUT > /dev/stdout
echo Redirected to... (2 Replies)
Discussion started by: marcink
2 Replies
7. Shell Programming and Scripting
Hello.
Following recommendations for one of my threads, this is working perfectly :
#!/bin/bash
CNT=$( grep -c -e "some text 1" -e "some text 2" -e "some text 3" "/tmp/log_file.txt" )
Now I need a grep success for some thing like :
#!/bin/bash
CNT=$( grep -c -e "some text_1... (4 Replies)
Discussion started by: jcdole
4 Replies
8. UNIX for Dummies Questions & Answers
How to use "mailx" command to do e-mail reading the input file containing email address, where column 1 has name and column 2 containing “To” e-mail address
and column 3 contains “cc” e-mail address to include with same email.
Sample input file, email.txt
Below is an sample code where... (2 Replies)
Discussion started by: asjaiswal
2 Replies
9. Shell Programming and Scripting
Hi,
I am using awk here.
Inside an awk script, I have a variable which contains a very long XML data in string format (500kb).
I want to pass this data (as argument) to curl command using system function.
But getting Too many arguments error due to length of string data(payloadBlock).
I... (4 Replies)
Discussion started by: cool.aquarian
4 Replies
10. Shell Programming and Scripting
Dear Ladies & Gents,
I have a requirement to delete all the log files in /var/log/test directory that are older than 10 days and their first line begin with "MSH" or "<?xml" or "FHS". I've put together the following BASH script, but it's erroring out:
for filename in $(find /var/log/test... (2 Replies)
Discussion started by: Hiroshi
2 Replies
COMM(1) User Commands COMM(1)
NAME
comm - compare two sorted files line by line
SYNOPSIS
comm [OPTION]... FILE1 FILE2
DESCRIPTION
Compare sorted files FILE1 and FILE2 line by line.
When FILE1 or FILE2 (not both) is -, read standard input.
With no options, produce three-column output. Column one contains lines unique to FILE1, column two contains lines unique to FILE2, and
column three contains lines common to both files.
-1 suppress column 1 (lines unique to FILE1)
-2 suppress column 2 (lines unique to FILE2)
-3 suppress column 3 (lines that appear in both files)
--check-order
check that the input is correctly sorted, even if all input lines are pairable
--nocheck-order
do not check that the input is correctly sorted
--output-delimiter=STR
separate columns with STR
--total
output a summary
-z, --zero-terminated
line delimiter is NUL, not newline
--help display this help and exit
--version
output version information and exit
Note, comparisons honor the rules specified by 'LC_COLLATE'.
EXAMPLES
comm -12 file1 file2
Print only lines present in both file1 and file2.
comm -3 file1 file2
Print lines in file1 not in file2, and vice versa.
AUTHOR
Written by Richard M. Stallman and David MacKenzie.
REPORTING BUGS
GNU coreutils online help: <http://www.gnu.org/software/coreutils/>
Report comm translation bugs to <http://translationproject.org/team/>
COPYRIGHT
Copyright (C) 2017 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.
SEE ALSO
join(1), uniq(1)
Full documentation at: <http://www.gnu.org/software/coreutils/comm>
or available locally via: info '(coreutils) comm invocation'
GNU coreutils 8.28 January 2018 COMM(1)