UNIX for Advanced & Expert Users

# Assuming there are no other kind of pdf files in that directory.

Code:

for i in *.pdf; do
  t=${i% * * * * * * * *.pdf}
  mv "$i" "${t% *}_${t#* }.pdf"
done

Interesting, gotta try that:

Code:

$ t='1 2 3 4 5 6 7 8 9 0'
$ echo ${t% * * *}
1 2 3 4 5 6 7
$

looks destructive!

Comparing read and $(line); line is a c program that does read(buf,0,1) until it finds a line feed, and then prints the line. It does not take more off the input stream than the one line, unlike read which uses a FILE* gets()/fgets() that reads ahead. Then, read trims white space when assigning the fields to one or more variables. However, $(line) costs a fork and exec, while read is ksh builtin and buffered. Apparently, it only affects edge whitespace:

Code:

$ echo ' a  b  c '|read z;echo "X${z}X"
Xa  b  cX
$

It's just parameter expansion with lazy pattern matching...

@Scru1Linizer

Doesn't you code assume there is a fix number of single space in the name of the initial file to move ?

Ow, you're right, I thought is was a fixed pattern.

Yes, but once you lose parts of i as you create t, how do you get them back?

Code:

t="$i"
while [ "$t" != "${t# }" ]
do
 t=${t% *}_${t##* }
done

tr is certainly easier.

Retry, let's take it from the other side:

Still assuming there are no other kind of pdf files in that directory.

Code:

for i in *.pdf; do
  t=${i%%${i#* * }}; t=${t% }
  mv "$i" "${t% *}_${t#* }.pdf"
done