bash: Bad Substitution

string bash ubuntu substitution
Arindam Choudhury picture Arindam Choudhury · Dec 16, 2013 · Viewed 266k times · Source 
#!/bin/bash

jobname="job_201312161447_0003"
jobname_pre=${jobname:0:16}
jobname_post=${jobname:17}

This bash script gives me Bad substitution error on Ubuntu. Any help will be highly appreciated.

Answer

Vanni Totaro picture Vanni Totaro · Dec 16, 2013

The default shell (/bin/sh) under Ubuntu points to dash, not bash.

me@pc:~$ readlink -f $(which sh)
/bin/dash

So if you chmod +x your_script_file.sh and then run it with ./your_script_file.sh, or if you run it with bash your_script_file.sh, it should work fine.

Running it with sh your_script_file.sh will not work because the hashbang line will be ignored and the script will be interpreted by dash, which does not support that string substitution syntax.

Related questions

How to check if a string contains a substring in Bash

I have a string in Bash: string="My string" How can I test if it contains another string? if [ $string ?? 'foo' ]; then echo "It's there!" fi Where ?? is my unknown operator. Do I use echo and grep? if echo "$string" | …

Read More
Extract filename and extension in Bash

I want to get the filename (without extension) and the extension separately. The best solution I found so far is: NAME=`echo "$FILE" | cut -d'.' -f1` EXTENSION=`echo "$FILE" | cut -d'.' -f2` This is wrong because it doesn't …

Read More
How to trim whitespace from a Bash variable?

I have a shell script with this code: var=`hg st -R "$path"` if [ -n "$var" ]; then echo $var fi But the conditional code always executes, because hg st always prints at least one newline character. Is there a simple …

Read More