hi all
by using cat /etc/passwd
I've got these output.
ajh1ect:x:839:501:Anthony:/home/ajh1ect:/bin/bash
mjb1ect:x:840:501:Michael:/home/mjb1ect:/bin/bash
mv3ect:x:841:501:Marian:/home/mv3ect:/bin/bash
now I want to see just the user ID and group ID.
so what is the code will be with... (2 Replies)
Hello. I am an older newbie trying to learn Unix. I have a task to perform and it entails counting lines of code. Currently, I am pointing to the directory where the files are contained and performing a 'find' on the file extensions (cpp, c, html, java, etc.) and piping that info with a 'wc -l'.... (2 Replies)
I have two .txt files one called good.txt and the other one is called bad.txt. Both contain email addresses in the following format:
john@john.com
bob@bob.com
sarah@sarah.com
Basically, I want to scrub good.txt against bad.txt and save the resulting output in scrubbed.txt meaning that if... (2 Replies)
------------------------------------------------------------------
Ex of Warning messgae,(Many similar lines occure for Both Test and Test1)
-WARNING:Below Field not implemented in file File name: /home/test/
new/file1, msg buffer is:
:Test:000948
... (1 Reply)
Hello all,
Can anyone help with the following? :)
I have file1 with 150,000 words in a list and file2 with 148,000 words in a list - all of which are in file1. I want to create a new file with the words that DO NOT match (i.e of 2000 words). I have done this very simple command , which is... (1 Reply)
Hi All,
I have a huge file, I need to two things from this file. I need to know the IP address or the hostname and second thing is the date&time.
The file looks like this and I need to get my data from this...
Trying...
Connected to 204.109.172.117.
Escape character is '^]'.
Fri... (4 Replies)
thanks for your reply.
but i'm not quite sure what your code is doing.
i may be using it wrong but i'm not getting what i'm supposed to get.
could you please elaborate?
thanks again, (6 Replies)
Thread1 {
x = 2
y = 10485
}
Thread2 {
x = 16
y = 1048
}
Thread3 {
x = 1
y = 1049
}
Thread4 {
x = 4
y = 1047
z = 500
}
Suppose the above is a piece of code. I need to automate and verify that the value of x under Thread1's 2.
There are several... (3 Replies)
Hi everyone!
I have a file like this
And I would like to find the Medium label when the value "last write" is "Jan 14" (it's could be another value like "jan 6")
I really don't know what way to use to solve this problem...
Thanks! (5 Replies)
Discussion started by: Castelior
5 Replies
LEARN ABOUT OPENDARWIN
subst
subst(n) Tcl Built-In Commands subst(n)
__________________________________________________________________________________________________________________________________________________NAME
subst - Perform backslash, command, and variable substitutions
SYNOPSIS
subst ?-nobackslashes? ?-nocommands? ?-novariables? string
_________________________________________________________________DESCRIPTION
This command performs variable substitutions, command substitutions, and backslash substitutions on its string argument and returns the
fully-substituted result. The substitutions are performed in exactly the same way as for Tcl commands. As a result, the string argument
is actually substituted twice, once by the Tcl parser in the usual fashion for Tcl commands, and again by the subst command.
If any of the -nobackslashes, -nocommands, or -novariables are specified, then the corresponding substitutions are not performed. For
example, if -nocommands is specified, command substitution is not performed: open and close brackets are treated as ordinary characters
with no special interpretation.
Note that the substitution of one kind can include substitution of other kinds. For example, even when the -novariables option is speci- |
fied, command substitution is performed without restriction. This means that any variable substitution necessary to complete the command |
substitution will still take place. Likewise, any command substitution necessary to complete a variable substitution will take place, even |
when -nocommands is specified. See the EXAMPLES below. |
If an error occurs during substitution, then subst will return that error. If a break exception occurs during command or variable substi- |
tution, the result of the whole substitution will be the string (as substituted) up to the start of the substitution that raised the excep- |
tion. If a continue exception occurs during the evaluation of a command or variable substitution, an empty string will be substituted for |
that entire command or variable substitution (as long as it is well-formed Tcl.) If a return exception occurs, or any other return code is |
returned during command or variable substitution, then the returned value is substituted for that substitution. See the EXAMPLES below. |
In this way, all exceptional return codes are ``caught'' by subst. The subst command itself will either return an error, or will complete |
successfully.
EXAMPLES
When it performs its substitutions, subst does not give any special treatment to double quotes or curly braces (except within command sub-
stitutions) so the script
set a 44
subst {xyz {$a}}
returns ``xyz {44}'', not ``xyz {$a}'' and the script |
set a "p} q {r" |
subst {xyz {$a}} |
return ``xyz {p} q {r}'', not ``xyz {p} q {r}''. |
When command substitution is performed, it includes any variable substitution necessary to evaluate the script. |
set a 44 |
subst -novariables {$a [format $a]} |
returns ``$a 44'', not ``$a $a''. Similarly, when variable substitution is performed, it includes any command substitution necessary to |
retrieve the value of the variable. |
proc b {} {return c} |
array set a {c c [b] tricky} |
subst -nocommands {[b] $a([b])} |
returns ``[b] c'', not ``[b] tricky''. |
The continue and break exceptions allow command substitutions to prevent substitution of the rest of the command substitution and the rest |
of string respectively, giving script authors more options when processing text using subst. For example, the script |
subst {abc,[break],def} |
returns ``abc,'', not ``abc,,def'' and the script |
subst {abc,[continue;expr 1+2],def} |
returns ``abc,,def'', not ``abc,3,def''. |
Other exceptional return codes substitute the returned value |
subst {abc,[return foo;expr 1+2],def} |
returns ``abc,foo,def'', not ``abc,3,def'' and |
subst {abc,[return -code 10 foo;expr 1+2],def} |
also returns ``abc,foo,def'', not ``abc,3,def''.
SEE ALSO
Tcl(n), eval(n), break(n), continue(n)
KEYWORDS
backslash substitution, command substitution, variable substitution
Tcl 7.4 subst(n)