small function to create n spaces between words. Useful with utils like sed/awk/cat

spacer.sh

sp() { printf "%0.0s " $(seq 1 $1); }

Example:

# Say you need to add two lines near the end of /etc/security/limits.conf
Orig file:
#<domain>      <type>  <item>         <value>
#
#*               soft    core            0
#root            hard    core            100000
# End of file

Desired file:
#<domain>      <type>  <item>         <value>
#
#*               soft    core            0
#root            hard    core            100000
*                soft    nofile          100000
*                hard    nofile          100000
# End of file

# Instead of manually putting spaces in using sed like so:
sed '$i*                soft    nofile          100000\n\*                hard    nofile          100000' /etc/security/limits.conf

# You can use this function to create the spaces
sed "\$i\*$(sp 16)soft$(sp 4)nofile$(sp 10)100000\n\*$(sp 16)hard$(sp 4)nofile$(sp 10)100000" /etc/security/limits.conf

# Note if using single quotes with sed, you'll have to put double quotes within the single qutoes when calling the function.
# WHile it results in a longer command, the precision is arguable better than manually spacing the words out.
sed '$i*'"$(sp 16)"'soft'"$(sp 4)"'nofile'"$(sp 10)"'100000\n*'"$(sp 16)"'hard'"$(sp 4)"'nofile'"$(sp 10)"'100000' /etc/security/limits.conf