How can I strip first X characters from string using sed?

bash shell sed
Kokesh picture Kokesh · Jul 13, 2012 · Viewed 229.8k times · Source

I am writing shell script for embedded Linux in a small industrial box. I have a variable containing the text pid: 1234 and I want to strip first X characters from the line, so only 1234 stays. I have more variables I need to "clean", so I need to cut away X first characters and ${string:5} doesn't work for some reason in my system.

The only thing the box seems to have is sed.

I am trying to make the following to work:

result=$(echo "$pid" | sed 's/^.\{4\}//g')

Any ideas?

Answer

chepner picture chepner · Jul 13, 2012

The following should work:

var="pid: 1234"
var=${var:5}

Are you sure bash is the shell executing your script?

Even the POSIX-compliant

var=${var#?????}

would be preferable to using an external process, although this requires you to hard-code the 5 in the form of a fixed-length pattern.

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