The shell is unix's command-line interface. You can type commands in a shell interactively, or write scripts to automate tasks. Use this tag for questions applying to /bin/sh and most compatible shells (ash, bash, ksh, zsh, …).

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4
votes
4answers
210 views

Convert key=value blocks to CSV

I am trying to transpose a content of a file into another. I am new to shell scripting any help would be really appreciated Input file Test.txt: HLRSN = 3 IMSI = 404212109727229 KIVALUE = ...
4
votes
4answers
47 views

Renaming multiple files with rename

I need help renaming files in batch--the other questions I browsed don't exactly address my problem. The names of my files are generated non-deterministically, so I can't predict what they will be ...
0
votes
0answers
10 views

How to pass multiple commands via pssh and multiple xterms

I'm attempting to open multiple xterms and run a command as an SAP user via sudo using pssh. So far, I'm able to run PSSH to a file of servers with no check for keys, open every xterm in the servers ...
5
votes
1answer
19 views

Getting the process-id out of command launched with “su -c”

I am running a java program inside a shell and writing the process-id to a text file. So when I do this: nohup java app.Main > /dev/null 2>&1 & echo $! > /var/run/app.pid It works. ...
2
votes
2answers
43 views

Create an absolute symbolic link to the current directory

I am now under a directory with very long path. For future visiting it quicker, I would like to create a link to it. I tried ln -s . ~/mylink ~/mylink actually links to ~. So can I expand ~ into ...
1
vote
1answer
23 views

How to find the cpu and memory usage of child processes

Supervisord is running on centos server. If I do ps -e -o %mem,%cpu,cmd | grep supervisord | awk '{memory+=$1;cpu+=$2} END {print memory,cpu}' I get 0 0 just because supervisord is just an ...
0
votes
1answer
603 views

Converting update-rc.d redis_6379 defaults to chkconfig command

I'm trying to run the commmand below to Centos and of course I get command not found. How do I then convert it to chkconfig ? update-rc.d redis_6379 defaults
1
vote
1answer
34 views

Who does the linewrap and how to deactivate?

If I connect to a linux device via serial adapter (no matter if pyserial, screen or minicom), and no matter how I change settings like stty when I enter a long command it gets line wrapped ...
14
votes
7answers
1k views

How do I repeat the last command without using the arrow keys?

I know I can use Up to iterate through previous commands. Running the last command simply involves Up + Enter. However, I was thinking of buying the Happy Hacking Keyboard as I spend a lot of time in ...
2
votes
2answers
25 views

Read Multiple Entries from an Input File

I wrote a program in Fortran that asks me for latitude and longitude and the name of the output file every time I run it. It works great. What I have been meaning to do is run this program for the ...
2
votes
2answers
27 views

Variable assignment outside of case statement

In many languages it is possible to assign the result of a case/switch statement to a variable, rather than repeating the variable assignment many times within the case statement. Is it possible to ...
2
votes
1answer
125 views

How does execution of !find command work?

The !find command lets the user perform the previously executed find, with all its parameters. How does it work internally, where exactly has this behaviour been programmed?
2
votes
2answers
27 views

Select a range of files after sorting them

One thing I notice slower for me if I switch from using a GUI file manager to CLI is: In a GUI file manager, I can quickly select a subset of files under a dir by, first sorting them according to ...
0
votes
1answer
475 views

Why alias does not work in AIX (korn shell, .profile)?

I have these files in my home directory: drwxr-xr-x 3 meuser staff 256 Oct 12 13:11 . drwxr-xr-x 102 bin bin 4096 Sep 30 12:28 .. -rw------- 1 meuser staff ...
19
votes
2answers
771 views

Does ~ always equal $HOME

I know this has probably been asked before, but I couldn't find it with Google. Given Linux Kernel No configurations that change $HOME bash Will ~ == $HOME be true?
0
votes
0answers
22 views

Detach a process from Sh (not Bash) or “disown” for Sh (not Bash)

Consider a shell script executed by Sh, not Bash (and I can't change it, and can't use a shebang, it's ignored). The & operator works, but disown $! does not and makes Sh complains “disown: not ...
8
votes
3answers
286 views

What is the difference of -a and -e in bash's conditional expressions?

From man bash: CONDITIONAL EXPRESSIONS [...] -a file True if file exists. [...] -e file True if file exists. So what is the difference between [ -a $FILE ...
0
votes
0answers
18 views

Cortex Application [on hold]

Cortex Acquirer & Issuer is a software application supporting a wide range of card payments functionality including Debit, Credit and Prepaid card issuing, card management and authorisation, ...
0
votes
1answer
34 views

Compare two strings in a shell script [duplicate]

My script needs two arguments. I want to hide the error message if someone calls the script with script.sh --help so I tired this: if [ $# -ne 2 ] ; then if [ "$1" -ne "--help" ]; then echo ...
1
vote
3answers
143 views

What is $() in a command?

What is $() in Linux Shell Commands? For example: chmod 777 $(pwd)
4
votes
0answers
45 views

How do I execute in background / return early?

For reference, I'm using phpseclib to control a remote SSH server using the 'root' account. I have to start/stop a java process which is ran in the background. Stopping works fine with killall java ...
0
votes
1answer
27 views

What is the term “Usage”?

I am seeing this a lot in the scripts. Is "usage" a command in unix ? I tried googling it but got ambiguous results. Here is an example : ${1?"Usage: $0 ARGUMENT"}
2
votes
2answers
67 views

Ping multiple hosts and execute command

I'm very new in bash scripting and unix so I will need some help on this.I have 7-10 hosts which I want to ping from one of the servers via cronjobs. What I want is when host is up to execute command ...
0
votes
2answers
29 views

change boot order

I have 2 partitions sda1 XP and sda2 CENTOS. I have reinstalled grub on /dev/sda but on rebooting, I experienced: error : 22 no such parition for Centos; while Windows boots charmingly on the other. ...
0
votes
1answer
36 views

How to evaluate a variable length in shell script?

I want to write a shell script, in which it will call different command according to the variable length. But I didn't figure it out yet. My unwork script is here: for i in n5 n25 if ${#i} == 2; ...
2
votes
1answer
20 views

Change the PS1 prompt in a subshell sh called from parent bash

When I am running an interactive bash session, I sometimes experiment with sh. I call sh directly from this bash session. My question is, how can I change the PS1 prompt of this subshell? I would ...
8
votes
6answers
371 views

How can I test if a variable is empty or contains only spaces?

The following bash syntax verifies if param isn't empty: [[ ! -z $param ]] For example: param="" [[ ! -z $param ]] && echo "I am not zero" No output and its fine. But when param ...
20
votes
6answers
2k views

Using VI keys to edit shell commands in UNIX

I used to have a co-worker who was really good at UNIX. He showed me how to use Vi key bindings to edit my shell commands. He placed the command in a file that ran every time I logged in. Since ...
1
vote
3answers
4k views

SSH to a host and enter password with shell script [duplicate]

I want to create a file like this : sshTOhost : #!bin/bash ssh -D 1500 user@host #enter password (I don't know how) can any one help me?
0
votes
1answer
41 views

Answer password prompt programmatically via shell script

I would like to programmatically answer a password prompt using only shell script when prompted. Is it possible to automate this task in this way? I want to avoid other tools entirely - so no expect ...
6
votes
6answers
512 views

How can I reproduce commands run on one machine on another machine?

I would like to install some software on a linux-machine that I have run in VirtualBox. Then I would like to do the same thing on a linux-VPS. I think that I can save all commands that I run using ...
1
vote
1answer
28 views

Recover files after moving directory names?

During the course of some testing, I ran the bast script for file in *; do mv -v "$file" "$file#_*" done or something along those lines. The plan was to remove a prefix from directory names ...
1
vote
2answers
49 views

If statement question

I am scratching my head to understand this script and can certainly use some expert advice. getopt_simple() { echo "getopt_simple()" echo "Parameters are '$*'" until [ -z "$1" ] do ...
4
votes
3answers
369 views

how to get the basename of complicated files [duplicate]

Here is an example of file path: /isf/GCM/VPfig/Aas/AR/ClCo el Doma Republic/VMN CRTro.txt What I want to get is the file basename: VMN CRTro.txt So I try the following: echo ...
2
votes
1answer
389 views

KSH styling text based menu using STDERR

Is it possible to format the STDERR in order to have a better looking menu using the select command? I have a simple select select oChoice in $(<tempMenu.menu) ; do case "$oChoice" in ...
0
votes
3answers
29 views

Finding and replacing text inside awk block

I want to find and replace a value inside awk block. Here is a sample input file to my script P1 10,9:11/18013013582 ,10:1 ,167:0 ,487:5/E.164 11,9:15/310410532169026 ,10:60 ,167:0 ,487:4/IMSI ...
48
votes
12answers
16k views

Get exit status of process that's piped to another

I have two processes foo and bar, connected with a pipe: $ foo | bar bar always exits 0; I'm interested in the exit code of foo. Is there any way to get at it?
2
votes
2answers
59 views

How to change my script to replace and add new variable in a configuration?

Well this is my script. It is to configure my systems sysctl.conf. infile = open('sysctl.conf') outfile = open('sysctl.conf.new', 'w') replacements = {'Net.ipv4.icmp_echo_ignore_all' :'1', ...
0
votes
0answers
11 views

Chrome OS: Crosh Window and Hostname

I have a couple of questions regarding Chrome OS: By default Ctrl+Alt+T opens a crosh window within the Chrome browser. I have the Crosh Window extension, which I would like Ctrl+Alt+T bound to - ...
3
votes
2answers
640 views

Replace a pattern in a file with a long string

I'm writing a little shell script to generate a directory listing. To make the output easily customizable, the script just builds a HTML-table and than should replace a specific token in a template ...
44
votes
8answers
8k views

How do I delete a file whose name begins with “-” (hyphen a.k.a. dash or minus)?

How do you remove a file whose filename begins with a dash (hyphen or minus) -? I'm ssh'd into a remote OSX server and I have this file in my directory: tohru:~ $ ls -l total 8 -rw-r--r-- 1 me ...
4
votes
2answers
2k views

Escaping quotes in zsh alias

Following on from this question about stripping newlines out of text, I want to turn this into a zsh alias as follows: alias striplines=' awk " /^$/ {print \"\n\"; } /./ {printf( \" %s \",$0);}"' ...
1
vote
1answer
43 views

regenerate xorg.conf with current settings

Many people have talked about this issue but I've not found a satisfactory answer. I'm on a debian jessie. Currently I have tried nvidia-driver as the driver but it caused the system to crash; so I ...
8
votes
3answers
204 views

Going into a directory linked by a link

When I cd a link, my current path is prefixed with the link's path, rather than the path of the directory the link links to. E.g. ~/dirlinks/maths$ ls -l logic lrwxrwxrwx 1 tim tim 71 Jul 27 10:24 ...
2
votes
1answer
45 views

Forward SIGTERM to child in Bash

I have a Bash script, which looks similar to this: #!/bin/bash echo "Doing some initial work...."; /bin/start/main/server --nodaemon Now if the bash shell running the script receives a SIGTERM ...
11
votes
13answers
2k views

How to read an IP address backwards?

If we have this string (IP address): 192.168.1.1 How can I derive the (DNS reverse record form) from this string, so it will be shown like 1.1.168.192.in-addr.arpa using a shell script?
1
vote
1answer
629 views

Deleting Non-empty Directory with smbclient

How can I remove a non-empty directory with smbclient? I have tried the following: 1) rm Result: NT_STATUS_NO_SUCH_FILE listing [dir_path] 2) recurse;rm Result: No Error but also nothing ...
14
votes
3answers
943 views

What does it mean to be “sh compatible”?

I've seen the phrase "sh compatible" used usually in reference to shells. I'm not sure if it also applies to the programs that might be run from within shells. What does it mean for a shell or other ...
0
votes
3answers
53 views

grep substring between quotes

Let's say I have a string like this: title="2010-09-11 11:22:45Z" How can I grep the date itself and disregard the quotes/title/Z? The file can contain more strings like: randomstring ...
4
votes
4answers
112 views

Check if content of file has length X and contains only specific characters

Let's say, I have files that contain only one docker id: myid.id: 28fe2baadbe8da32ed0b99c69b11c01b2d141bc5b732b81e0960086de52fc891 I want to check if the content of my.id is exactly 64 characters ...