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4
votes
1answer
145 views

Can I refer to a global variable even if a locally scoped one exists with the same name?

If I have a variable x total=3 and then a function function A () { local -i total=0 } Is there any way I can update the 'global' total variable total from within function A ?
1
vote
2answers
41 views

How to format decimal number to display the preciding zero but not the trailing ones?

I have the following script on Ubuntu 14.04.1 LTS 64-bit bash command prompt: S=0.030 F=0.150 N=10 reso=20 DIFF=`echo "scale=3; $F - $S" | bc -l` df=`echo "scale=3; $DIFF / $N" | bc -l` is=`echo ...
1
vote
2answers
26 views

scripting- Ignoring a variable when undefined

HP-UX *** B.11.31 U ia64 **** unlimited-user license Hello, var1=abc var2=xyz touch $var1 $var2 $var3 if the one of the variable is not set the command fails with ksh: var3: parameter not set ...
1
vote
1answer
18 views

Comparing variables in arithmetic

Was wondering if someone can take the time to explain the following: I have a directory of files (PDF), which I place into an array. shopt -s nullglob # Set array ...
0
votes
2answers
44 views

How to use variables properly in this little script?

Here is a little script to retarget old-wrong symlinks that I want to make interactive. #!/bin/bash # retarget (broken) symbolink links interactively echo -n "Enter the source directory where ...
0
votes
1answer
25 views

Is there a valid way of exporting a variable across different shells?

For some reasons, Im using ksh and zsh in my scripts and returning to -bash, I need to use already set variable values in the spawned shells, writing it to some temp file and using that didn't look ...
0
votes
2answers
65 views

In a shell script, How to give a variable another value after one job is done?

I'm trying to make a script which will see if the directory exists and will zip all of its contents under it according to the name/path of the directory. The farthest I could go was - ...
1
vote
3answers
108 views

sed won't expand my BASH variable in script

I have this script, which will prompt for the relative or absolute path to the file and then swap whitespaces ' ' with '\ ' which works in Linux console. Substitution is done using the first sed ...
0
votes
1answer
34 views

How to assign the cat output of a bash script to a variable in another script

I have a bash script that produces a cat output when it takes an argument. I also have another bash script that executes the first bash script with an an argument that I want to produce cat outputs ...
2
votes
3answers
80 views

Using find with 2 sets of variables

I want to be able to run a find command in my bash script that will find files based on two seperate variables. I've gotten this far but I'm not sure how to get the final result workingfind . -user ...
2
votes
2answers
70 views

Using the output of `grep` as variable in second command

I currently have 2 bash command line strings I use to gather data needed for a certain task. I was trying to simplify and have only one command used to gather the data without using a script. First I ...
1
vote
1answer
38 views

Read from character delimted file and assign into variables | for email

I am using ksh. I need to read the data from file, into the variables and then further use them for sending emails. File can be delimited by any less used characters (like | ^ etc.) or group of ...
3
votes
2answers
117 views

Assign specific line from a variable to another variable

I would like to take a specific line from a variable to another variable. I tried this but it doesn't work: c="1.apple 2.banna 3.peach" read "Please choose fruit [1-3]:" t a=$c | awk "NR==$t" echo ...
0
votes
1answer
29 views

Insert variable value as element in array

If I have a variable that has a value stored and I want to place that value into an array using the name of the variable, how would I do this? e.g.: variable="Hello there" array[0]=$variable does ...
1
vote
3answers
50 views

Use a variable as part of name of an array name?

I essentially have a for loop where the variable i that I am iterating with will take on each letter of the alphabet, for example. I want to use each value of i to create an array called "$i"array ...
1
vote
1answer
45 views

Why doesn't my function work with spaces? (cd, dirname) [duplicate]

I have had this function I use it very often and it works fine. Here it is: cdx () { cd `dirname $1` ; } However, this does not work with spaces. When I use it like this for example cdx ...
1
vote
1answer
45 views

SQLPLUS value in variable- not working from crontab

I am trying to store sqlplus value to a variable in Linux. Script is working fine when triggered manually. But value in variable is not stored when the script is called from crontab. Code: ...
2
votes
1answer
34 views

Export path with space in directory name [duplicate]

I have a path "/third/party/city of las vegas" when cd the path I use "/third/party/city of las vegas". In .profile file I have exported the path to a variable as follows export ...
2
votes
2answers
100 views

How to use variables inside single quotes

I have an application which takes as an input attributes in double quotes embedded in single quotes. Take for example this right command: command -p 'cluster="cl1"' In order to automate it, I ...
3
votes
2answers
86 views

How to use tee to capture STDOUT from a code block to a filename defined within the block?

I want to send STDOUT for a script block to a file which name is defined by a variable within the block. However, when I use tee, it seems the variable outside the block doesn't exist anymore. Without ...
-1
votes
1answer
28 views

what directory is used to execute “expr” command,what holds it process-id and log record [closed]

What directory execute the expr command. What directory holds the the PID of the command. What directory hold the log file of this command.and how to read all these??
4
votes
3answers
161 views

Using | pipe character from a $variable makes it treat as just another argument in bash; how to escape it?

I have a bash script like this export pipedargument="| sort -n" ls $pipedargument But it gives the error ls: |: No such file or directory ls: sort: No such file or directory It seems to be ...
4
votes
2answers
180 views

Running commands stored in shell variables

The following works in my shell (zsh): > FOO='ls' > $FOO file1 file2 but the following doesn't: > FOO='emacs -nw' > $FOO zsh: command not found: emacs -nw even though invoking emacs ...
2
votes
1answer
66 views

Why string comparision results always false

I am trying to do a one time check about apache's mod-status page for updates like this(this is just a test script): firstcontent=$(lynx -dump http://some-server/server-status-page) echo ...
2
votes
4answers
313 views

Extracting the second word from a string variable

I have a string "rtcpOnNbActive true" stored in a variable x. I want to extract "true" as substring and store in a variable. How can I do this?
2
votes
3answers
85 views

How can I print only variables defined inside my shell script?

Lets supose some bash shell script like: #!/bin/bash a=3 b=7 set -o posix set In this case, the execution of the set variable or some other of the commands to print environment variables ...
0
votes
2answers
56 views

How can I expand all variables at the command line in Zsh?

In an earlier question, specific to bash, I asked How can I expand a relative path at the command line, with tab completion? I liked @Mikel's answer that mentioned using Ctrl+Alt+e to expand all ...
13
votes
2answers
860 views

How can variables use “~” for cd'ing?

How can I use a variable - $BASE in my cd. I tried the following but I get an error $ cd ~/z/repo_1_ruby_193/ 23:23:57 durrantm Castle2012 /home/durrantm/z/repo_1_ruby_193 $ BASE="~/z" 23:24:03 ...
1
vote
1answer
59 views

How do I define alias with variables which can be changed at runtime?

This is probably a very easy to answer question, but I could not find any questions already asking this due to different wording when writing titles. Running help alias on my bash prompt returns only ...
2
votes
1answer
41 views

Append same timestamp to multiple filenames

I have several files that I ftp each hour. The receiving system needs to have some sort of identifier that they came from the same batch, so I would like to append a timestamp to the filename. That ...
2
votes
1answer
179 views

Error passing variable from bash to php

I have the following files: vars.txt C=1234567890 Ascript.php #!/usr/bin/php <?php var $C="$argv[1]"; echo "\n $C \n"; $con = mysql_connect('localhost','root','123') or die ("No connected"); ...
1
vote
1answer
89 views

Get two values from command output in a bash script

I have a bashscript, which executes a command and calculates a pair of values, which output can look like this. a,b (10.0000000000, 10.0000000000) -> volt (2088133.7088034691, -222653.3238934391) ...
1
vote
0answers
74 views

passing variable through cat EOF command with for loop

How do I get the script run with the sbatch command to run with the 23 individual run_prep_chem_$dd.sh (i.e. run_prep_chem_08.sh...run_prep_chem_30.sh)? I am thinking since its in this for loop that ...
3
votes
3answers
72 views

How can I base the file name off of an already existing variable?

I'm using this to delete lines that don't match a pattern: $ egrep "pattern1|pattern2|pattern3|pattern4|pattern5" But now I need to do it automatically, so I'm setting a variable like this: $ ...
4
votes
8answers
2k views

How to assign a string value to a variable over multiple lines while indented?

The issue: I need to assign a variable a value that is decently long. All the lines of my script must be under a certain number of columns. So, I am trying to assign it using more than one line. ...
6
votes
4answers
913 views

shortest way to replace characters in a variable

There are many ways to replace characters in a variable. The shortest way I found out is tr so far: OUTPUT=a\'b\"c\`d_123and_a_lot_more OUTPUT=$(echo "$OUTPUT"|tr -d "'\`\"") echo $OUTPUT Is ...
6
votes
5answers
387 views

Number of characters in a shell command's output

I am writing a script which needs to calculate the number of characters in a command's output in a single step. For example, using the command readlink -f /etc/fstab should return 10 because the ...
0
votes
2answers
112 views

Bash Mysql Command Substitution Login Failure

Bash and MySQL versions: GNU bash, version 4.2.25(1)-release (x86_64-pc-linux-gnu) mysql Ver 14.14 Distrib 5.5.37, for debian-linux-gnu (x86_64) using readline 6.2 I have a bash script that tries ...
4
votes
1answer
88 views

Length of argument inside a function of an sh script

I have a FreeBSD 9.3 RELEASE server and I am trying to write a shell script using sh. I am trying to get the length of a variable that is passed to a function in a shell script, like so: #!/bin/sh ...
3
votes
2answers
722 views

Assign Subshell background process pid to variable

I am currently starting a background process within a subshell and was wondering how can I assign its pid number to a variable outside the subshell scope? I have tried many different ways but MYPID ...
4
votes
1answer
440 views

Bash: Variable assignment doesn't seem to 'stick' [duplicate]

I am having a hard time tracking down the reason my 'boolean' flag variable won't stay false when a test fails inside a while loop. The script involves a few loops but essentially it is intended to ...
4
votes
2answers
107 views

Shell script error handling while assigning STDOUT to variable

I am trying to implement error handling in my shell script as described in the 2nd answer in Best practice to use $? in bash? My script looks like this: #!/bin/bash try() { "$@" code=$? ...
2
votes
1answer
639 views

Storing whitespace in a shell script variable [duplicate]

I need to store specific number of spaces in a variable. I have tried this: i=0 result="" space() { n=$1 i=0 while [[ "$i" != $n ]] do result="$result " ((i+=1)) ...
3
votes
5answers
2k views

How to use a shell variable inside sed's s command? [duplicate]

we know that we can get the value of a variable using $ sign: x=3 echo $x 3 Is there other ways that we can use to get the value without using $ sign. I'm asking this because $ sign is a special ...
6
votes
3answers
391 views

Attempted assignment to non-variable?

We can use arithmetic operations inside shell script function: function mess { if (( "$1" > 0 )) ; then total=$1 else total=100 fi tail -$total /var/adm/messages | more } I ...
3
votes
2answers
169 views

Command substitution declaration syntax in bash - which of these two is better practice? [duplicate]

This is part of a bash find loop, and I wondered which is more correct syntax and why? filename="$(echo "$i" | cut -c5-)"; filename=`echo "$i" | cut -c5-`; Both function for the purpose of getting ...
1
vote
1answer
226 views

How can I use global variable arrays in aliases or functions

I am attempting to simplify repetitive work procedures. In doing so, I am trying to write a .bashrc script which will set global path variables that aliases can refer to. Disclaimer: I'm new to linux ...
5
votes
1answer
596 views

ifconfig -a in a shell script

I am writing a shell script to start my network in my virtual machine on boot, since it does not do this right away for some reason with a snapshot of a virtual machine. Since the eth device starts ...
2
votes
1answer
77 views

Could “>” be included in a bash Variable?

Current approach: sudo awk 'BEGIN{printf "<?xml version=\"1.0\" encoding=\"utf-8\"?>\n<hello>\n\t<world>\n";} {print "\t\t",$0}END{printf "\t </world>\n</hello>\n"}' ...
1
vote
1answer
2k views

command not found in shell script

Please tell me why I couldn't print variable value. # chmod 777 chkscript.sh # ./chkscript.sh chkscript.sh file content variable = "This is variable" echo "$variable" echo "Hello World " ...