To reduce run time you need to use shell builtins as much as possible and not call external programs such as awk.
Even if ksh is *much* faster then bash for this type of parsing I often found that awk was faster than pure shell solutions in reading and processing lines. To make sure, I just ran a benchmark on a sample file with 20000 lines using Franklin52's awk snippet and the following ksh93 code:
Results:
awk: 0.146 sec.
ksh: 0.636 sec.
So, awk is five times faster albeit being an external program. And, just for the record, I also tested a bash version and, as expected, it's the slowest:
I have been working on some code for a while, that will parse a log file, look for a specified time discrepancy between entries, and then print that line +/- n other lines out to a file...
#!/bin/bash
file=$1 # The input log file
maxTime=$2 # The time discrepancy to look for
n=$3 ... (1 Reply)
dear pro-coders,
is there any command out there that takes out the front spaces from a string?
sample strings:
4 members
5 members
3 members
but it has to be like so:
4 members
5 members
3 members (3 Replies)
Hi all!
i need your help.
I'm getting started with this...
in need to insert in an array string values. But the thing is that this strings have blank spaces...
for example if a want to put "filed1 = " and "field2 = " .... in the array , when i want to print all the fields, it only shows... (4 Replies)
Forgive me. I am very new to kornshell scripts. The simplest things stop me dead in my tracks.
Here are two such examples.
I want to save the first 19 characters of the following string to a variable.
"Operation Completed and blah blah blah"
I know this works (from another thread):
... (2 Replies)
Hi,
Could someone has any suggestions on this? When read a line from a file, I need to check the first char in the line, it could be a space or any char. But the leading spaces are removed by read.
Thanks. (2 Replies)
Hi,
Well as the title says, I have an array of strings (delimited by null). The length of the array is variable and length of each string is variable as well. What I need is one huge string with the original strings in the array separated by spaces.
For example is an array is such that array... (12 Replies)
'String' file contains the following contents,
D11, D31, D92, D29, D24,
using ksh, I want to remove all white spaces between characters no matter how long the string is.
Would you please give me some help? (1 Reply)
I have a file, names(i) where each entry is 'first last' name. 'cat names' is fine. But in a shell script
>for file in $(cat names)
> do
> echo $file
> done
the first and last name appear on 2 lines. I have tried escaping and quoting the space but to no avail. The names are to be... (4 Replies)
I'm having issue capturing a value from file.list with a multiple spaces in a variable $i, tried various options like using double quotes, no quotes, single quotes, curly braces but to no avail.
cat file.list
aaa test bbb
ccc test ddd
eee test fff
for i in `cat file.list`
do
echo "$i";... (2 Replies)
Hi
I'm trying to loop through an array that contains other arrays and these arrays consist of strings with spaces. The problem is that I can't seem to preserve the spacing in the string. The string with spaces are either divided into multiple items if I change IFS to \n or all the elements of... (4 Replies)
Discussion started by: kidmanos
4 Replies
LEARN ABOUT DEBIAN
rbash
RBASH(1) General Commands Manual RBASH(1)NAME
rbash - restricted bash, see bash(1)RESTRICTED SHELL
If bash is started with the name rbash, or the -r option is supplied at invocation, the shell becomes restricted. A restricted shell is
used to set up an environment more controlled than the standard shell. It behaves identically to bash with the exception that the follow-
ing are disallowed or not performed:
o changing directories with cd
o setting or unsetting the values of SHELL, PATH, ENV, or BASH_ENV
o specifying command names containing /
o specifying a file name containing a / as an argument to the . builtin command
o specifying a filename containing a slash as an argument to the -p option to the hash builtin command
o importing function definitions from the shell environment at startup
o parsing the value of SHELLOPTS from the shell environment at startup
o redirecting output using the >, >|, <>, >&, &>, and >> redirection operators
o using the exec builtin command to replace the shell with another command
o adding or deleting builtin commands with the -f and -d options to the enable builtin command
o using the enable builtin command to enable disabled shell builtins
o specifying the -p option to the command builtin command
o turning off restricted mode with set +r or set +o restricted.
These restrictions are enforced after any startup files are read.
When a command that is found to be a shell script is executed, rbash turns off any restrictions in the shell spawned to execute the script.
SEE ALSO bash(1)GNU Bash-4.0 2004 Apr 20 RBASH(1)